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Discussion Starter · #1 ·
I have a 302/5.0l that I want to stroke. I have looked at both the 331 and the 347 kits. I am leaning towards the 347. WIth the 347 you get two cubic inches percylinder more over the 331. And there is no replacement for displacement.

I have heard the horror stories about oil burning from the 347. I tend to not believe them. There are just to many 347s on the street that don't burn oil to make it the fault of the design. And blow by from the top ring is what helps the oil ring do it's job. I wonder if the builder made too tight a gap on the top ring, just a thought. And I have heard about rod length ratio but then again there are a lot of motors out there that run fine with a worse ratio.

So my question is how many people have actually run a stroked 347 and what, if any problems have you seen? Also please give some idea s to how you drove your stroker. Track, towing daily driver or what.

This is not going in a mustange. It's going in a Lincolin Town car that weighs six thousand pounds empty, I really need the extra torque from the 347. ANd I m going to drop in a converted AOD transmissionthat as the wide ratio gears from the AODE. This lower range will give an advantage from the line for quick take offs.
Or at lest as quick as can be expected from a land yaught. I rebuilt the total suspension when I was on chemo for large B-cell lymphoma.It was good therapy. I could lie in bed a feel like **** or I could get up and work on the car an feel like ****. It wasn't easy, One time I had to break lose a bolt on the front suspension. My body was very week. I pulled very hard and all that happened was my face got smashed into the control arm, splitting my forehead. This pissed me off so much I worked well into the night. The suspension is completely done. From rubber on the road to ball joints and new bushing, front and rear, and special springs getting it ready for a good engine. I would like a 347 but some say it burns oil but some don't burn oil. So what did you do with your 347 if you built one?

TIA
 

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It is in the machining and clearance tolerances.
If you know you have a very good machinist, that's "gold".
You have to be anal about your tolerances. "good enough" won't cut it here.
You have two choices of rod length;
5.4" (original) Ronnie Crawford I'm told was the first to do this.
5.315" (new school) came about to pull the pin out of the ring land.

If you have questions, I'll be more than happy to answer or get you the correct answer you need for the direction you're going.

Dana
 

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That oil burning problem of the 347 is a thing of the past, they've improved the internals and now you could get a ring package that will seal the cylinder, eliminating the excessive blow by.
Yes, the long rods tend to elongate the bottom of the cylinders but with proper maintenance a 347 can live a long life.
Also know that a 331 makes just as much torque as the 347 so both are great strokers to have.
 

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Discussion Starter · #4 ·
It is in the machining and clearance tolerances.
If you know you have a very good machinist, that's "gold".
You have to be anal about your tolerances. "good enough" won't cut it here.
You have two choices of rod length;
5.4" (original) Ronnie Crawford I'm told was the first to do this.
5.315" (new school) came about to pull the pin out of the ring land.

If you have questions, I'll be more than happy to answer or get you the correct answer you need for the direction you're going.

Dana
As far as I can tell only Probe offers the pistons and rods for the 5.315 version with the wrist pin not in the oil control ring. The cost for this is MUCH more then the other version.

When I first started to think about doing this I found probe had a piston with an offset wrist pin. This sounded like a great idea to compensate for the rod length to stroke ratio. But I haven't seen anything about it from probe after they went with an outside company to do their retail sales, I forget their name off the top of my head. Maybe they are still offset and nobody mentions it or they have gone back to the normal configuration.

One of the things that gives me pause for the 5.315 version is the length of the skirt on the piston. Normally I like short skirts but not on pistons. This worries me, I don't like piston slap. And I think you are right if you have a short skirted piston you need your tolerances to be right on.

I am leaning towards the 5.4 length kits with the wrist pin hole in the oil control ring. The cost I save in the rotating assembly can go to get a better machinist.

Dana you didn't say what version you are running. Could you post that and any thing you might want to add?
 

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I am using the Probe Ultralight 5.315 rods.
Probe SRS 1.175" CH flat top pistons.
Scat 3.4" lightened forged crank.
The assembly has been balanced to 28oz imbalance.
The Cylinders have been bored, honed with a final finish hone and polish to Probes recommended diameter. If I had my receipt here at home I'd give you that dimension.
My pistons came with a ring package, they were file fit and the manufacturer slips my mind. If you have to know... I can contact my supplier, he'll know.
If I forgot anything, just ask.

I have no idea why I decided on the 5.315" rod... in hindsight all I accomplished was installing a heavier piston.
IMO I should have gone with the longer rod.
 
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