[347Vert]

Originally Posted by Old man

The level of maturity and humility in a debate here rivals that of congress.

Been a exceptionally busy week. I will accept my response was lame and regurgatory, and was an attempt to delay to when I have more time to respond with an adequate one. Small step above congress wouldn't you agree in the sense I am actually working I will have more time this weekend to make a few more points if interested in continuing this little debate.

[n2omike]

Originally Posted by 347Vert

Anyone research Ford's reasoning yet? It's not just to serve a simple nitch in the market, but is set on research and sound principles in building race motors. Which one of you is going to take these arguments to Ford Racing professionals, and challenge their reasoning? Let me know when you do and how far you get.

Well, it was the Ford professionals that screwed up the new Boss 302 block. It was them that messed up and made it with short 4-3/4" long cylinders, where the stock ones, at 5" to 5-1/8" were already some of the shortest in the industry. When you build a 3.400" stroke (347) engine with one, a significant portion of the wrist pin actually descends BELOW the bottom of the cylinder. Go ahead, do the math. You'll see. There is very little piston skirt support at BDC when the piston is rocking and changing direction. Personally, I wouldn't run any more than a 3.25" stroke with one, if even that. I'd use as long of a rod as possible with a stroker to get the pin as high as it could go at BDC, that's for sure. It may be one reason Ford decided to change direction and offer the block with the 3.100" stroke that was mentioned.

An Official Amen to my fellow Mustang Brothers.......many I hope I can say in CHRIST.

I don't have any problems with your right to your religion in your own home/church, but we aren't there, and I don't really need preached to on an automotive techincal site. Your signature is plenty.

[347Vert]

Originally Posted by n2omike

Well, it was the Ford professionals that screwed up the new Boss 302 block. It was them that messed up and made it with short 4-3/4" long cylinders, where the stock ones, at 5" to 5-1/8" were already some of the shortest in the industry. When you build a 3.400" stroke (347) engine with one, a significant portion of the wrist pin actually descends BELOW the bottom of the cylinder. Go ahead, do the math. You'll see. There is very little piston skirt support at BDC when the piston is rocking and changing direction. Personally, I wouldn't run any more than a 3.25" stroke with one, if even that. I'd use as long of a rod as possible with a stroker to get the pin as high as it could go at BDC, that's for sure. It may be one reason Ford decided to change direction and offer the block with the 3.100" stroke that was mentioned.

Sounds like you are supporting the 331 and another good point. I will add more later supporting the 331 in an all out race motor debate. I am not debating combined street/strip use, as I am in full support of either build, and actually lean towards the extra torque of the 347 when talking mainly street use - I chose one.


I don't have any problems with your right to your religion in your own home/church, but we aren't there, and I don't really need preached to on an automotive techincal site. Your signature is plenty.

Another member opened the door for my comments mentioning sermons and collections, otherwise I would not have added beyond my signature. Comments were not intended to be "preachy", but a sincere hope and prayer to keep this above the fray in brotherhood and not tread into potential sarcasm or sacrilege either. Enough said about this subject let's get back to strokers.

"Single biggest factor affecting side loading is the rod length to stroke ratio. The shorter the rod is in relation to the stroke, the greater the angularity it goes through" (Resource MMFF Nov. 2007 Stroker Strategies). In other words, friction and vibration concerns.

I think all will agree friction effects horsepower. The worse the R/S ratio this only increases side loading friction, but also greatly increases the chance of ring seal loss or reliability due to piston skirt scuffing the cylinder wall.

Another factor with poor rod/stroke ratio is torsional vibrations (again side loading due to rod angularity). Torsional vibrations can effect the longevity of parts, mainly crank breakage, and can even "upset the cam dynamics leading to spurious valve bounce" (same source as above).

Combine a worse rod/stroke ratio and the above factors with a significant high rpm use of a motor and it can spell eventual disaster. I purport Ford Racing chose the 331 as they wanted a reliable race crate motor that inherently had a better rod/stroke ratio than the 347 - minimizing the above factors, especially when winding past 7,000rpm.

[n2omike]

Originally Posted by 347Vert

I purport Ford Racing chose the 331 as they wanted a reliable race crate motor that inherently had a better rod/stroke ratio than the 347 - minimizing the above factors, especially when winding past 7,000rpm.

The change in friction between r/s ratios between around 1.5 and 1.8 (which is the general range) is not THAT significant. It's there, but not that great.

When it comes to making horsepower, the dynamics of the pumping system are far more important. With heads that are restrictive for the given combination, longer rods can indeed make more power. However, today, there are plenty of GOOD heads out there that are properly sized, if not even a tad oversized for the engines they are being used on. Shorter rods actually help get the air/fuel charge moving in these engines, as the shorter r/s ratios don't dwell the piston at TDC and BDC like a long rod does. It sweeps the piston through this area more quickly and keeps the air/fuel moving.

The reason Ford Racing went to the 3.100" stroke engine with the 4.125" bore was because the Boss block is DEFECTIVE. They screwed up and made it with 4-3/4" long cylinders! As I said on the last page, stock cylinders are between 5" and 5-1/8" long. With the short cylinder and a 3.4" (typical 347) stroke, the bottom of the pin actually descends BELOW the bottom of the cylinder.
The Math...

Bore length is 4.75"

typical pin height of 3.400" stroke (347) piston = 1.100"
stroke = 3.400"

3.400" + 1.100" = 4.500"

This means the center of the pin is 4.500" below the top of the cylinder at the bottom of its travel, leaving only 0.25" of cylinder below the pin's centerline. But, remember, the pin is close to an inch in diameter. (0.912" or 0.927" depending on the parts chosen) so close to a 1/4" of the pin is going to extend below the bottom of the cylinder with these blocks! This only leaves a very small amount of the piston skirt to support the piston at BDC. Not good.

The 3.100 stroke gives plenty of room for proper support, and when combined with the 4.125" bore provided the 331ci that people are familiar and "comfortable" with.

[Jay Allen]

Originally Posted by 347Vert

"Single biggest factor affecting side loading is the rod length to stroke ratio. The shorter the rod is in relation to the stroke, the greater the angularity it goes through" (Resource MMFF Nov. 2007 Stroker Strategies). In other words, friction and vibration concerns.

1. If [and that is a big if] side loading were an issue, then YES I can agree to the above.

2. If you believe 25% of what is in a magazine, then you are in big trouble. They are comic books at best.

Originally Posted by 347Vert

I think all will agree friction effects horsepower. The worse the R/S ratio this only increases side loading friction, but also greatly increases the chance of ring seal loss or reliability due to piston skirt scuffing the cylinder wall.

This is partly a half truth.

Of the CONVENTIONAL STROKER KITS AVAILABLE, if you assemble a kit and have a ring seal issue, it is on YOU [plural] and it is NOT the fault of the kit.

And when you say reliability, are you not old enough to remember the junk pistons that cam in OEM engines in the 1960's, 1970's, and the early 1980's? Couple that with a 1.48 R:S ratio in a 400 SBC and according to what you type, this would be a recipe for a disaster.

But it was not.

Originally Posted by 347Vert

Another factor with poor rod/stroke ratio is torsional vibrations (again side loading due to rod angularity). Torsional vibrations can effect the longevity of parts, mainly crank breakage, and can even "upset the cam dynamics leading to spurious valve bounce" (same source as above).

Okay, seriously, I have had enough.

You are typing and using big words. You are throwing around phrases and trying to sound like an authority. This is not High School and sounding cool does not earn brownie points.

1. How much of a delta change in "torsional vibrations" can I expect to encounter between a 3.25" stroke using a 5.400" rod and a non off set pin VS a 3.400" stroke using a 5.400" rod and an off set pin?

2. This change in "torsional vibrations", how much more life will this suck out of the 347 vs the 331?

3. Lastly, here is where your theory is blown up, RPM is far more of killer than is anything you can dream up. A 331 will ALWAYS have to turn more RPM to do get as much work accomplished as a 347 can. So this increase in RPM that the 331 will go through, now factor that into your equation.

***This is the problem with these discussions. They are on paper and based on theory. They are ONE SWEEP of a piston and measuring the load, ONE TIME. They do not take into account what happens in the REAL world. OK, so your 331 has less "Torsional Vibration" on paper than my 347. But my 347 will always have a 4.41% advantage in RPM reduction due to piston speed. And this does not take into account the better piston design of the 347's pin being offset.

Originally Posted by 347Vert

Combine a worse rod/stroke ratio and the above factors with a significant high rpm use of a motor and it can spell eventual disaster. I purport Ford Racing chose the 331 as they wanted a reliable race crate motor that inherently had a better rod/stroke ratio than the 347 - minimizing the above factors, especially when winding past 7,000rpm.

I have 20 - 25 customers weekly. I can say w/o a shadow of a doubt that the customer who wants to turn 7000 RPM and above VS the customer who wants to turn 7000 RPM and below is about 1 in 25-30.

Very few people have near enough induction to turn 6500 RPM, little lone 7000 RPM. They get all hung up in more paper theories about velocity and low end TQ so they buy a restrictor plate for their 302 stroker.

It is exactly poor information on internet forums that leads to where we are today. This thread is a fine example.

There is NO REASON not to build a 347. A 331 will make less power and do a pooer job than a 347. The people who cannot get a ring to seal are exactly the guys who talk bad about a 347. Instead of figuring out what they have done wrong and admitting fault, its easier to sound in telligent and talk about torsional vibration and never admitting fault.

Last question I will ask: 347Vert, how many 331's have you built and how many 347's have you built? Experience here counts.......

[Joel5.0]

Originally Posted by 347Vert

"Single biggest factor affecting side loading is the rod length to stroke ratio. The shorter the rod is in relation to the stroke, the greater the angularity it goes through" (Resource MMFF Nov. 2007 Stroker Strategies). In other words, friction and vibration concerns.

That is a simple lesson in geometry. IOW.... yes... angularity of the rod is increased = fact

At what point is angularity that detrimental to engine life regardless of its use, but under constant load conditions? What is its real contribution in determining engine reliability and endurance = unknown + facts point at other factors to affect engine durability. Here's a local using a Toy 1.8L 3T-C engine (1.577 R:S.. or right in between both 347 configurations), Turbo with Nitrous, racing RPM range in the 8200+. He's the owner of the shop that does 98% of the work for my shop.

YouTube - Rafy Machine Shop

Does he refresh that engine every 6 months, 1 year, 2 years?...... ... is it a monster of an engine performing like that?.... take a look = http://dragueo.tv/home/reportajes/rafy/images/2.jpg ... and again, what about all the OEM examples = fact?

Originally Posted by 347Vert

I think all will agree friction effects horsepower. The worse the R/S ratio this only increases side loading friction, but also greatly increases the chance of ring seal loss or reliability due to piston skirt scuffing the cylinder wall.

Another factor with poor rod/stroke ratio is torsional vibrations (again side loading due to rod angularity). Torsional vibrations can effect the longevity of parts, mainly crank breakage, and can even "upset the cam dynamics leading to spurious valve bounce" (same source as above).

Combine a worse rod/stroke ratio and the above factors with a significant high rpm use of a motor and it can spell eventual disaster.

Any engine poorly built will not survive...... 289, 302, 331, 347, 357, 363, etc, etc..... it's not an issue of one single factor but the sum of the configuration as a whole.

Originally Posted by 347Vert

I purport Ford Racing chose the 331 as they wanted a reliable race crate motor that inherently had a better rod/stroke ratio than the 347 - minimizing the above factors, especially when winding past 7,000rpm.

Why didn't they choose the big bore 347 version instead? 3.250 x 4.125....... would it be that unreliable due to its R:S to offer it as a race product? Why didn't they go with a 3" or 2.870" R:S configuration and a 4.125" bore if R:S was that important?

Again.... don't take this the negative/wrong way, but you are falling under a hasty generalization based on a single product from a company that offers all the other "less reliable" configurations as well, or were those under-engineered? ... street and race. Add the factual data gathered from the field, and that line from that magazine article is simply what it is intended to be...... a marketing slogan. And that should not be the cause to have anybody decide for a 331 over a 347.

[347Vert]

Originally Posted by n2omike

The change in friction between r/s ratios between around 1.5 and 1.8 (which is the general range) is not THAT significant. It's there, but not that great.

When it comes to making horsepower, the dynamics of the pumping system are far more important. With heads that are restrictive for the given combination, longer rods can indeed make more power. However, today, there are plenty of GOOD heads out there that are properly sized, if not even a tad oversized for the engines they are being used on. Shorter rods actually help get the air/fuel charge moving in these engines, as the shorter r/s ratios don't dwell the piston at TDC and BDC like a long rod does. It sweeps the piston through this area more quickly and keeps the air/fuel moving.

The reason Ford Racing went to the 3.100" stroke engine with the 4.125" bore was because the Boss block is DEFECTIVE. They screwed up and made it with 4-3/4" long cylinders! As I said on the last page, stock cylinders are between 5" and 5-1/8" long. With the short cylinder and a 3.4" (typical 347) stroke, the bottom of the pin actually descends BELOW the bottom of the cylinder.
The Math...

Bore length is 4.75"

typical pin height of 3.400" stroke (347) piston = 1.100"
stroke = 3.400"

3.400" + 1.100" = 4.500"

This means the center of the pin is 4.500" below the top of the cylinder at the bottom of its travel, leaving only 0.25" of cylinder below the pin's centerline. But, remember, the pin is close to an inch in diameter. (0.912" or 0.927" depending on the parts chosen) so close to a 1/4" of the pin is going to extend below the bottom of the cylinder with these blocks! This only leaves a very small amount of the piston skirt to support the piston at BDC. Not good.

The 3.100 stroke gives plenty of room for proper support, and when combined with the 4.125" bore provided the 331ci that people are familiar and "comfortable" with.

If this were the case, would MMFF do a Project called "Stolen Goods" that in fact uses a Boss block and 347 kit? Your the first one who has told me about how poorly designed they are, yet they are flying off the shelves and major mustang magazines are using them for projects. So what gives?

[Joel5.0]

Originally Posted by 347Vert

If this were the case, would MMFF do a Project called "Stolen Goods" that in fact uses a Boss block and 347 kit? Your the first one who has told me about how poorly designed they are, yet they are flying off the shelves and major mustang magazines are using them for projects. So what gives?

Yes... they used the 331 rotating assembly (limiting the stroke to 3.250") and went big bore (4.125") to net the 347 cid engine.... read = Tom Naegele Discusses The Ford Racing Performance Parts Boss 302 Block - Muscle Mustangs & Fast Fords Magazine ... and guess which was the reason.......

The Boss has a shorter cylinder length, which makes rod bolt clearancing of the cylinders obsolete, but it may limit the amount of stroke and compression height you can run. The bigger you go on stroke, the more the piston protrudes out of the bottom of the cylinder. The Boss cylinders are approximately 0.400-inch shorter in length than a stock or R block.

As you can see, even your magazine based knowledge confirms some facts..... and it also proves how it can be easily manipulated.... and as n20mike described based on hands-on experience....... the Boss Block shorter cylinder walls are a fact.

[347Vert]

Originally Posted by Jay Allen

1. If (and that is a big if) side loading were an issue, then YES I can agree to the above.

So when is rod/stroke an issue with you? Just because it does not jell with your belief your willing to throw it out totally and discredit?

2. If you believe 25% of what is in a magazine, then you are in big trouble. They are comic books at best.

Any comic book (MMFF) that backs up their theories with dyno or drag tests on a regular basis I'm subscribing to.

This is partly a half truth.

Of the CONVENTIONAL STROKER KITS AVAILABLE, if you assemble a kit and have a ring seal issue, it is on YOU [plural] and it is NOT the fault of the kit.

I agree, unless you are seeing significant rpm and have a poor rod/stroke ratio.

And when you say reliability, are you not old enough to remember the junk pistons that cam in OEM engines in the 1960's, 1970's, and the early 1980's? Couple that with a 1.48 R:S ratio in a 400 SBC and according to what you type, this would be a recipe for a disaster.

IMHO it would if you are looking to race = over 7,000 rpm on a regular basis. Again, my argument lies in race motors not in street or street/strip cars 6500 or under. Again, side load friction and torsional vibrations compound as you increase rpms. I don't need a engineering degree to know that - it is common sense.

But it was not.

Okay, seriously, I have had enough.

You are typing and using big words. You are throwing around phrases and trying to sound like an authority. This is not High School and sounding cool does not earn brownie points.

Getting personal here? You getting frustrated and for what reason? I'm proposing points based on my experience and information I have garnered over the years. I never said that I am authority, but I am willing to share what knowledge I have without personal attacks as that is more high schoolish than anything else posted here.

1. How much of a delta change in "torsional vibrations" can I expect to encounter between a 3.25" stroke using a 5.400" rod and a non off set pin VS a 3.400" stroke using a 5.400" rod and an off set pin?

I'm not an engineer, but I can give you a common sense view on facts saying the torsional vibrations are higher in a 347 and especially compounded the higher the rpms you go.

2. This change in "torsional vibrations", how much more life will this suck out of the 347 vs the 331?

Over 7,000 rpms on a consistent basis in a race motor I bet pretty significant - at least I believe Ford Racing would think so also. They want to maintain their reputation for good and reliable crate motors wouldn't you agree?

3. Lastly, here is where your theory is blown up, RPM is far more of killer than is anything you can dream up. A 331 will ALWAYS have to turn more RPM to do get as much work accomplished as a 347 can. So this increase in RPM that the 331 will go through, now factor that into your equation.

Here is where we agree as RPM is what I am talking about. Combine high rpm with increased side loading and torsional vibrations = reliability issues. Again, this is reason a 331 was chosen.

***This is the problem with these discussions. They are on paper and based on theory. They are ONE SWEEP of a piston and measuring the load, ONE TIME. They do not take into account what happens in the REAL world. OK, so your 331 has less "Torsional Vibration" on paper than my 347. But my 347 will always have a 4.41% advantage in RPM reduction due to piston speed. And this does not take into account the better piston design of the 347's pin being offset.

I acknowledge a 331 will have to turn higher rpms to make up the 16 cubic inch difference. However, as the rpms rise torsional vibrations and side loading frictions quickly start closing the gap between the two. I would almost bet past 7500, by the way this would be a great dyno test for MMFF, the 331 would start walking away from a 347 due to less friction and torsional vibrations.

I have 20 - 25 customers weekly. I can say w/o a shadow of a doubt that the customer who wants to turn 7000 RPM and above VS the customer who wants to turn 7000 RPM and below is about 1 in 25-30.

Very few people have near enough induction to turn 6500 RPM, little lone 7000 RPM. They get all hung up in more paper theories about velocity and low end TQ so they buy a restrictor plate for their 302 stroker.

Again, my argument does not lie with people under 7,000 rpm. Staying under, I agree go with the 347 for more torque.

It is exactly poor information on internet forums that leads to where we are today. This thread is a fine example.

Who's playing the authority now? How did you assume this position that others cannot disagree with you?

There is NO REASON not to build a 347. A 331 will make less power and do a pooer job than a 347. The people who cannot get a ring to seal are exactly the guys who talk bad about a 347. Instead of figuring out what they have done wrong and admitting fault, its easier to sound in telligent and talk about torsional vibration and never admitting fault.

I have never had a motor not obtain ring seal in the beginning, but I have had two 347's that have struggled to maintain after a short period of time. Both motors had significant scuffing or side loading, way above normal for a small block ford, that contributed to the eventual loss of ring seal. Yes, rpm was a factor also. This led to my research on the cause and importance of rod/stroke ratios.

Last question I will ask: 347Vert, how many 331's have you built and how many 347's have you built? Experience here counts.......

I've built about 30 motors in my day with over half race - mainly 351's. I've been a wall fly at Tom Straley's, very reputable circle track motor builder in the mid west, in Hastings, MI on several occasions. My father has rebuilt probably over 350 motors in his day of which about 1/4 I've observed or helped. I really don't care to get in experience pissing matches. If you have some experience and take time to research from various sources, then you should be able to enter the arena of ideas without having your credibility attacked for sharing an opposite opinion.

Originally Posted by Joel5.0

Yes... they used the 331 rotating assembly (limiting the stroke to 3.250") and went big bore (4.125") to net the 347 cid engine.... read = Tom Naegele Discusses The Ford Racing Performance Parts Boss 302 Block - Muscle Mustangs & Fast Fords Magazine ... and guess which was the reason.......

As you can see, even your magazine based knowledge confirms some facts..... and it also proves how it can be easily manipulated.... and as n20mike described based on hands-on experience....... the Boss Block shorter cylinder walls are a fact.

You are correct - I stand corrected as I did not readily recall their particular configuration, but interesting to note though it has the better rod/stroke ratio doesn't it in their project?

Please do not misinterpret my lack of responses for conceding as previously posted by a member. I have another busy week and likely will not be able to post until next weekend. Have a great week fellas and please pardon me for saying GOD BLESS.

[Joel5.0]

Originally Posted by 347Vert

You are correct - I stand corrected as I did not readily recall their particular configuration, but interesting to note though it has the better rod/stroke ratio doesn't it in their project?

They HAD to....... if they were limited by the block, they had to work with what was available.

[89coupe]

In other words, to market their block( which they screwed the pooch on) they had to use the 3.250 stroke

[Jay Allen]

"Concede" there is nothing to "Concede".

This is not game or warfare. Education & Experience are not about getting a guy to concede, its about getting the proper information out there.

Sir, I am NOT saying that a 347 does not have MORE sideload as tested on an engine stand for ONE piston sweep. This is true. But with a 347 getting the same work done at a lower RPM that extends the life of the engine. With the better pin in a 347 and a lower overall RPM used, a 347.

While 50 engines is a good number, that was 1.5 months at Crawford. When I was BG's place, to build rebuild build and rebuild 50 times per 1 race season was nothing just to find 5hp or 1 or 2 pounds.

You or no one else on this board is capable of saying that a 331 is good for "this" and a 347 is good for 'that". Torsion loads, ring seal or anything else you want to bring up is so insignificant that talking about it is a waste of time

It falls back on the person who honed the block, what finish is on the block, the skirt clearance and where that clearance was measured, what rings and how the rings were filed that will make or break any engine. A 347 takes skill and seriously, most shops cannot do it. Sorry but that is a fact. A shop will never come back and say they screwed the pooch when in fact they did.

I have seen it for over 25 years now and it just gets worse instead of getting better.

There is too much misinformation about engines.

[Joel5.0]

Originally Posted by 347Vert

Any comic book (MMFF) that backs up their theories with dyno or drag tests on a regular basis I'm subscribing to.

So it's all on the presentation? BTW.... I don't see any engine reliability tests based on R:S on any magazine. Or a stress-wear analysis using a Spintron setup focused on R:S, to even derive conjectures that would still be challenged by the factual data on the field.

Originally Posted by 347Vert

I agree, unless you are seeing significant rpm and have a poor rod/stroke ratio.

Yet a "poor rod/stroke ratio" has been proven to be irrelevant in factual continuously documented cases.

Originally Posted by 347Vert

IMHO it would if you are looking to race = over 7,000 rpm on a regular basis. Again, my argument lies in race motors not in street or street/strip cars 6500 or under. Again, side load friction and torsional vibrations compound as you increase rpms. I don't need a engineering degree to know that - it is common sense.

However, that opinion is (and you continue to ignore that fact) challenged and nullified by factual experience, far exceeding the conditions you mentioned above inclusive..... not in a magazine.

Originally Posted by 347Vert

Getting personal here? You getting frustrated and for what reason? I'm proposing points based on my experience and information I have garnered over the years. I never said that I am authority, but I am willing to share what knowledge I have without personal attacks as that is more high schoolish than anything else posted here.

One thing is experience, a totally different thing is a C&P from a magazine article (as is this case). Or would you also believe the TPS adjustment fallacy/misinformation just because a magazine publishes it..... or because it is still printed in the FRPP catalog? Regardless of its source it still is misinformation.

Nevertheless, the frustration is obvious.... so let me do something here. Since you only focus on magazine articles to base your information/knowledge on, questioning actual hands-on experience. Check this little magazine extract of someone that has been working with 347, 331, 302, 289, 351c race engines for quite some time = Limited Pro 1998

Was he using a 331 then? .....

Originally Posted by 347Vert

I'm not an engineer, but I can give you a common sense view on facts saying the torsional vibrations are higher in a 347 and especially compounded the higher the rpms you go.

Again, that does not explain the factual results on the field in terms of endurance, performance and reliability.

Originally Posted by 347Vert

Over 7,000 rpms on a consistent basis in a race motor I bet pretty significant - at least I believe Ford Racing would think so also. They want to maintain their reputation for good and reliable crate motors wouldn't you agree?

If they limit themselves to a single factor in engine design, w/out engineering the ripple effect that single factor can cause........ they are leaving competitivenes on the table..... product and professional wise.

Originally Posted by 347Vert

Here is where we agree as RPM is what I am talking about. Combine high rpm with increased side loading and torsional vibrations = reliability issues. Again, this is reason a 331 was chosen.

Again the facts collected over the years do not support that theory/speculation.

Originally Posted by 347Vert

I acknowledge a 331 will have to turn higher rpms to make up the 16 cubic inch difference. However, as the rpms rise torsional vibrations and side loading frictions quickly start closing the gap between the two. I would almost bet past 7500, by the way this would be a great dyno test for MMFF, the 331 would start walking away from a 347 due to less friction and torsional vibrations.

Yup.... just like this 347 vs 331 video clip..... in which the 331 needed NOS in order to barely loose to the N/A 347...... Grant 331 nos Mustang vs. Dan 347 N/A Mustang With - Car Videos on StreetFire

Originally Posted by 347Vert

Again, my argument does not lie with people under 7,000 rpm. Staying under, I agree go with the 347 for more torque.

If you build a 347 correctly, no need to worry about RPM's over a 331.

Nobody is attacking you, again..... it's the isolation of R:S as the determining factor for performance or reliability, when there has been more than enough cases that do not ID it as a significant factor. Is it something to ignore?.... no, yet it also is a factor that does not pose the control it is attributed. If that is the case...... 351w strokers above the 393 cid's would self destruct or require rebuilding every year or two..... and that too, is not the case.

[Jay Allen]

Originally Posted by 347Vert

So when is rod/stroke an issue with you? Just because it does not jell with your belief your willing to throw it out totally and discredit?

Its not. When did I say it was? You assume I think it is. I know HOW it is DONE at REAL race shops. I have said this. Plus, based on YOUR skill, please give me a stroke, a rod length, and a piston compression THAT WILL ACTUALLY BOLT TOGETHER and the R:S is an issue?

I guess the FOUR HUNDRED CUBIC INCH SMALL BLOCK CHEVROLET THING has not sunk in yet. Here is what I will do. I will BURY you with EXAMPLES that run and make more steam than you can dream of. Please get your calculator out and tell me how it works.

Originally Posted by 347Vert

Any comic book (MMFF) that backs up their theories with dyno or drag tests on a regular basis I'm subscribing to.
I agree, unless you are seeing significant rpm and have a poor rod/stroke ratio.

You have NEVER been part of a magazine test. But to humor you, they have an end desired result that is PAID FOR by an outside source and those results are achieved come H*LL or high water.

If you believe a magazine test at MMFF then you get what you deserve.

Originally Posted by 347Vert

IMHO it would if you are looking to race = over 7,000 rpm on a regular basis. Again, my argument lies in race motors not in street or street/strip cars 6500 or under. Again, side load friction and torsional vibrations compound as you increase rpms. I don't need a engineering degree to know that - it is common sense.

First of all I am not an engineer either. Not sure why you even said that as it means nothing, yet. I asked for examples and all we get is I am not an engineer. Back up what you say as I have, Joel has, and anyone with any engine experience will do.

Race motors? If you are going to be technical, get it right. They are ENGINES. And you want to argue your point? OK, here is a list of engines built everyday that go directly against your point.

How about a 496 BBC?
How about a 540 BBC?
How about a 565 BBC?
How about a 598 BBC?
How about a 632 BBC?
How about a 400 SBC?
How about a 427 SBC?
How about a 434 SBC?
How about a 393 SBF?
How about a 408 SBF?
How about a 418 SBF?
How about a 427 SBF?
How about a 434 SBF?
How about a 445 SBF?

Want high end?

How about a 707 Top Sportsman BBC?
How about a 800+ CID Pro Stock Engine?

How about when I ran 9.52 in 1995 with a 347. Stock suspension, 28 x 10.5" MT tire (no "W"), race weight was 3180#, I made 217 total passes in 1994 late, all of 1985, and into 1996. I never took the short block apart. I turned it 9200 RPM on the gear change and 9600 RPM in the lights. I ran 9.29 at 2995 as I took the ballast out.

HP = (Weight x 197.65) / ET^3
HP = (2995 x 197.65) / (9.29)^3
HP = 738.3
738.3 / 347 = 2.13 HP/cid

Cast intake, single 4150 carb done by Billy Glidden, 2" header x 4" exhaust.
217 passes with no issue. Calculate that.......

Just imagine what would have happened if I had a 3.25" stroke!!!

This is not little league you are messing with now. I suggest you do more research on me.

Originally Posted by 347Vert

Getting personal here? You getting frustrated and for what reason? I'm proposing points based on my experience and information I have garnered over the years. I never said that I am authority, but I am willing to share what knowledge I have without personal attacks as that is more high schoolish than anything else posted here.

You keep talking as you are an authority and it is because of this boards rules. At sbftech.com or at the new HC50, you would have been cut off a long time ago.

Originally Posted by 347Vert

I'm not an engineer, but I can give you a common sense view on facts saying the torsional vibrations are higher in a 347 and especially compounded the higher the rpms you go.

OKAY, on a test stand for ONE revolution IT IS! I said that God D*mn it. But what does the off set pin do? And your 3.25" stroke will ALWAYS work HARDER to do the SAME job my 3.40" stroke will do at a LOWER RPM. here in a minute you even ACKNOWLEDGE THAT!!!

Okay, on a stand, 1 revolution, you win. But as an assembled piece, making passes, a 331 will EXPLODE due to the higher RPM REQUIRED to do perform the SAME work I am doing at a LOWER RPM.

DO YOU WISH TO FIND OUT HOW I KNOW THIS?

Originally Posted by 347Vert

Over 7,000 rpms on a consistent basis in a race motor I bet pretty significant - at least I believe Ford Racing would think so also. They want to maintain their reputation for good and reliable crate motors wouldn't you agree?

Hmmm.......
You "bet".......LOL

The engines are "reliable" because they don't make any steam. How do you know what FORD wants? More conjecture on your part. Do you know what FORD wants? MONEY.

Originally Posted by 347Vert

Here is where we agree as RPM is what I am talking about. Combine high rpm with increased side loading and torsional vibrations = reliability issues. Again, this is reason a 331 was chosen.

You are making a huge leap here. I ask again.

I want to KNOW the exact side load differences between the 331 & the 347. I want YOU to tell us. Then I want YOU to tell us all when the 347 will fail and how much of a longer life the 331 will have. PLEASE TAKE INTO ACCOUNT THE OFF SET PIN. PLEASE TAKE INTO ACCOUNT THE HIGHER RPM RANGE THE 331 WILL ENCOUNTER AS WELL.

Originally Posted by 347Vert

I acknowledge a 331 will have to turn higher rpms to make up the 16 cubic inch difference. However, as the rpms rise torsional vibrations and side loading frictions quickly start closing the gap between the two. I would almost bet past 7500, by the way this would be a great dyno test for MMFF, the 331 would start walking away from a 347 due to less friction and torsional vibrations.

You acknowledge a higher RPM is used but you said you weren't an engineer so don't pick and choose when you know something vs when you don't.

Originally Posted by 347Vert

Again, my argument does not lie with people under 7,000 rpm. Staying under, I agree go with the 347 for more torque.

You have no argument. I know how it is DONE at REAL high end shops. I know of 3 or 4 very high end engine guys (not motor guys) who post on the internet. Want me to have them march in here too?

Originally Posted by 347Vert

Who's playing the authority now? How did you assume this position that others cannot disagree with you?

Disagree all you want. But the TRUTH and FACTS about the TRACK don't lie.......but your Texas Instruments does.

Originally Posted by 347Vert

I've built about 30 motors in my day with over half race - mainly 351's. I've been a wall fly at Tom Straley's, very reputable circle track motor builder in the mid west, in Hastings, MI on several occasions. My father has rebuilt probably over 350 motors in his day of which about 1/4 I've observed or helped. I really don't care to get in experience pissing matches. If you have some experience and take time to research from various sources, then you should be able to enter the arena of ideas without having your credibility attacked for sharing an opposite opinion.

Let's focus on the best part here:

I really don't care to get in experience pissing matches

So actual experience on what has happened doesn't matter?
If you make a statement against fact it will get challenged. I have credibility as I am held accountable for what I say and do. People listen to me because of what I have done and what I help them do. I have earned respect and I am credible.

[n2omike]

Originally Posted by Jay Allen

It falls back on the person who honed the block, what finish is on the block, the skirt clearance and where that clearance was measured, what rings and how the rings were filed that will make or break any engine. A 347 takes skill and seriously, most shops cannot do it.

Jay, what does a 347 take that a 302 does not? Where do most shops screw up 347 builds? What specifics do they "like"?

Thanks!