Ford Mustang Forum banner

1 - 20 of 27 Posts

·
Registered
Joined
·
9 Posts
Discussion Starter #1
I have started restoring a very worn 1967 coupe. I will probably be wearing you guys out with questions and requesting your opinions.

The first thing I am dealing with is the engine. It had a 289 block with 351 heads. It was also running an HP cam. It ran great 30 years ago and I am thinking about going back with the same set up. I would like some feedback/opinions from you guys.

Thank you all very much and I hope you have a lot of patience....lol
Chuck
 

·
Registered
Joined
·
2,355 Posts
If they are not '69 or '70 heads, then they're really nothing special. (C9 or D0). Even if they are C9 or D0, without porting they are probably only on par with E7TE's, which are as common as sand on a beach. Not to say that the '69 or '70 heads are junk. In the hands of someone who knows how to work them, they have far more potential than any E7TE ever made.

Also, flat tappet cams are kind of a pain these days. You have to use specially formulated oils with ZDDP, or use additives.

My advice? Depending on if you want to drive it or sell it, you should strongly consider just getting a 5.0 HO motor from an Explorer or Mountaineer. Putting in a roller-cam motor may actually increase the value of your car, rather than hurting it, depending on how it's optioned. Unless there's something rare about your car, I'd say that a new roller cam motor is probably the way to go, whether you want to keep it or not.

The 98-01 versions come with GT40P heads, which are the best street heads Ford ever put on a 302. They have a roller cam, so you can use whatever oil you want. If it's not all sludged up, and under 150k miles, the bottom end should be perfect. All of your original engine's parts and accessories should fit, solving your oilpan (early Stangs are front sump) and fuel system issues. Just put in some better valvesprings (because the Explorer cam is a low-RPM truck cam without much lift, and the stock springs reflect that), and a better cam (a cheap factory Mustang 5.0 HO cam runs amazingly with these heads) and BAM. You're looking at an engine that can trounce a stock 289 Hi-Po without breaking a sweat, but runs on cheap pump gas and will possibly get you 25 mpg highway, based on your rear gears. It'll even run nice with an automatic.

If you can't find a GT40P motor in good shape for a reasonable price, or the headwork turns out to be expensive for some reason, I would not hesitate to find a set of aluminum heads. Even cheap Skip White heads or Edelbrocks are better than GT40P's, and they don't require special headers either. You can easily use your cast iron logs with 40P heads, so it's a non-issue unless you want to add headers. Basically, if reworking the 40P heads would cost you more than around $500, it would be foolish not to spend an extra $100 and just go with aluminum, selling the P heads to help pay for them. They're in high demand.

If you really want to keep your 289 block, and are willing to put up with the oil formulation issue, or maybe want to save a lot of money, just rebuild what you've got! Windsors are great little motors. If your bottom end is damaged enough to require oversize pistons, or the crank needs work, you might even think about getting a stroker kit. It'll end up being a similar price to going back to stock anyway. What carb and intake does it have?
 

·
Registered
Joined
·
9 Posts
Discussion Starter #3
If they are not '69 or '70 heads, then they're really nothing special. (C9 or D0). Even if they are C9 or D0, without porting they are probably only on par with E7TE's, which are as common as sand on a beach. Not to say that the '69 or '70 heads are junk. In the hands of someone who knows how to work them, they have far more potential than any E7TE ever made.

Also, flat tappet cams are kind of a pain these days. You have to use specially formulated oils with ZDDP, or use additives.

My advice? Depending on if you want to drive it or sell it, you should strongly consider just getting a 5.0 HO motor from an Explorer or Mountaineer. Putting in a roller-cam motor may actually increase the value of your car, rather than hurting it, depending on how it's optioned. Unless there's something rare about your car, I'd say that a new roller cam motor is probably the way to go, whether you want to keep it or not.

The 98-01 versions come with GT40P heads, which are the best street heads Ford ever put on a 302. They have a roller cam, so you can use whatever oil you want. If it's not all sludged up, and under 150k miles, the bottom end should be perfect. All of your original engine's parts and accessories should fit, solving your oilpan (early Stangs are front sump) and fuel system issues. Just put in some better valvesprings (because the Explorer cam is a low-RPM truck cam without much lift, and the stock springs reflect that), and a better cam (a cheap factory Mustang 5.0 HO cam runs amazingly with these heads) and BAM. You're looking at an engine that can trounce a stock 289 Hi-Po without breaking a sweat, but runs on cheap pump gas and will possibly get you 25 mpg highway, based on your rear gears. It'll even run nice with an automatic.

If you can't find a GT40P motor in good shape for a reasonable price, or the headwork turns out to be expensive for some reason, I would not hesitate to find a set of aluminum heads. Even cheap Skip White heads or Edelbrocks are better than GT40P's, and they don't require special headers either. You can easily use your cast iron logs with 40P heads, so it's a non-issue unless you want to add headers. Basically, if reworking the 40P heads would cost you more than around $500, it would be foolish not to spend an extra $100 and just go with aluminum, selling the P heads to help pay for them. They're in high demand.

If you really want to keep your 289 block, and are willing to put up with the oil formulation issue, or maybe want to save a lot of money, just rebuild what you've got! Windsors are great little motors. If your bottom end is damaged enough to require oversize pistons, or the crank needs work, you might even think about getting a stroker kit. It'll end up being a similar price to going back to stock anyway. What carb and intake does it have?
It has an edelbrock highrise and a Holley 600...I think... The carb may have to be replaced. I will let it soak a few days and take another look at it. I am not building it to race, show or sell, just building it to cruise occasionally.
 

·
Registered
Joined
·
2,355 Posts
If the Holley does need to be replaced, get yourself a Summit M-series 600 CFM carb. You would not regret it.
 

·
Registered
Joined
·
9 Posts
Discussion Starter #5
If the Holley does need to be replaced, get yourself a Summit M-series 600 CFM carb. You would not regret it.
I admire your knowledge of these engines. I know for a fact that the 5.0 is excellant. I bought an F150 brand new in 2000. I rebuilt the engine at 304000 miles though I probably could have got many more miles had I just changed the timing chain. Right now it has 620000 miles on it and I drive it every day. I am working on this Mustang with my step brother who has rebuilt/restored many Mustangs as well as other cars that have won many awards. He happens to be 80 years old...still working everyday! If I was to tell him I wanted to convert to a different style of engine.... well lets just say that would'nt be taken very well...lol.

Regardless if the engine I have can't be rebuilt, I will have a decision to make.
What do you believe would be the difference between going with the 351 heads/289 block with an hp cam compared to just running a regular 289 with an hp cam?

Tomorrow I will try to track the dates of the block and heads by using the casting numbers and report back what I find.
I have made a note on the Summit M series carb.
Thank you again for your help. I will be leaning on you greatlyfor the next few months...lol
 

·
Registered
Joined
·
9 Posts
Discussion Starter #6
I have found that the 289 block is a 1965 truck engine. It is the 5th version. Unfortunately I wrote down the wrong casting numbers on the heads. It may be Saturday before I can get over there to get the right numbers... I will be back when I get that info..
 

·
Registered
Joined
·
8,022 Posts
A 289 block is pretty much a 289 block. Car, truck or whatever, used the same blocks. If you mean change level 5, that was for late '64 into '65 so its pretty early for a 289. By end of production in 1968 289s were up to change level 16. Just for 1965 the change levels went from 5 thru 10.
 

·
Registered
Joined
·
9 Posts
Discussion Starter #8
The head casting number is DOOE. From what I could find they were built in 1970 for either a Fairlane or Torino. Under that casting number the letter C is there. I have no idea what that means.
The full casting number on the block is C5AE-6015E.
Hopefully this weekend I can drop them off at a shop to be vatted and checked.
I will get back shortly with the results.
Thanks!
 

·
Registered
Joined
·
2,355 Posts
As Ivy says, a 289 is pretty much a 289. The only exception being the very early ones, which had a 5 bolt transmission pattern that doesn't fit many transmissions. Later Windsors all got the same 6 bolt pattern. For that matter, a 302 block is more or less the same as a 289 also. Later, the 302 got called the '5.0', but again, mighty similar. Same bore, only some very minor differences which don't interfere with parts interchange. Later engines got a roller cam setup, and the lifter bores are a little different, which makes it pretty hard to just drop a roller cam into a 289. It can be done with a lot of machining, or by doing a reduced base circle cam. Some people like to make a big deal out of the extra length of the 302 block cylinders, but it's only about .040 if I remember right, and quite frankly, it means nothing. You can put a 289 crank in a 302, or a 302 crank in a 289 without much fuss. The earlier blocks and cranks use a 2 piece rear main seal. They can be machined to use the newer one-piece seal, if you feel like it. Again, not a big deal.

Your D0 351 heads in stock form (regardless of other letters) are comparable to the ho-hum E7TE heads that got put on every Mustang from 1987 till they dropped the 5.0. (excepting the Cobras which got GT40s for a year I think). The E7 heads can be improved *slightly* with porting, but not enough to make them worth the time or expense. Your D0 heads, on the other hand, have a lot of extra meat in the ports, and can be improved by a real pro to be at least as good as the GT40 heads, possibly even approaching stock GT40P heads in terms of flow, though not combustion chamber efficiency. They're one of the sought-after years for heads, simply because they're probably the very best 'vintage' heads you can get. Assuming yours have not been mangled by someone, they're worth having, or selling, depending on how you feel about them.

This cam business is kind of important. The old style flat-tappet cams will not survive long on modern oil. They took out the ZDDP, which helps cushion the sliding parts of the cam and lobes. If you have a low-lift, wimpy, stock 289 (not Hi-Po) cam, it might work okay for a while, but eventually, it will cause big problems. Additives, or expensive oil with ZDDP in it can help avoid this situation. It would be safe for a stock cam. A high performance cam's additional lift needs much stronger springs to keep the valvetrain in check. Combined with the higher RPMs, and increased friction from extra lift, it gets kind of 'iffy' even on additives. Flat tappet cams are a bit scary for a car you want to actually drive a lot, these days.

Modern roller cams were introduced in '85, I think, for the 5.0 motors. Just a rebadged 302. If your old block is really shot, you wouldn't have to sell it. You could put it into storage. Only a concourse judge would note the different stampings on a new 5.0 block if you used it in your car. All of your 289 accessories would bolt right up, including your 351 heads. You would have to get different valvesprings, and perhaps different pushrods, but the benefit of having a roller cam means better throttle response, economy, and best of all - no worries about all that ZDDP stuff and wrecked lifters/lobes.

So, the takeaway here: 289, 302, 5.0 = Almost exactly the same thing. Heads, timing cover, intake, everything interchanges. They look very much the same, aside from some stampings that are hard to spot without having the engine out of the car. 5.0 is best though, because of the roller cam, especially if you're trying to build on a reasonable budget. It's super easy to find a 5.0 in a salvage yard Ford, and they hardly have any wear on the pistons or cylinders if they're under 200k miles, unless they were abused.
 

·
Registered
07 Mustang GT
Joined
·
533 Posts
The flat tappet cam is not dead yet and there are plenty of oils still out there that they can survive with. I use Valvoline VR1 racing oil for street use. I would use what you have and pick a cam that suits your application. I'm still old school and just can't see myself putting a modern engine into an old car.
 

·
Registered
Joined
·
9 Posts
Discussion Starter #11
Please increase my knowledge... Is the 5.0 you speak of from 1985 the same animal that is in my 2000 F150? I always thought that a 5.0 was a 5.0 but I didnt think the new version of the 5.0 engine came out until 1997. If it is the more modern 5.0 that I am picturing, How does it get powered electronically? Fuel injection, COP's etc... Would you have to hook in a PCM? Would it become OBDII friendly?
These are probably dumb questions but there is only one way for me to learn...
Thanks again!
 

·
Registered
Joined
·
2,355 Posts
Chuck, starting around '85 (and someone please correct me if I've got my years wrong!) there were two versions of the 5.0 motor. One was used in all the run of the mill passenger cars and trucks, with cast pistons and a cam that would deliver good low-rpm torque, decent economy, but it didn't have much lift and was ill-suited to high performance use.

The 5.0 HO motor was identical in most ways, but had forged pistons until the early 90s when they switched to Hypereutectic. The fuel injectors on the HO were capable of squirting a bit more fuel, and the intakes were a little better, though some years they may have been the same. Standard 5.0 motors had dished pistons too, which lowered the compression a little. And lastly, the cam in the HO motors would let the engines wind out to a few more RPMs, producing more horsepower.


Typically, the standard 5.0 had about 200 horses, while the HO version was rated around 225. It varied just a few ponies from year to year. Mustangs and Lincoln sports coupes had the HO motors. Not sure if they were in V8 Thunderbirds. I am pretty sure even the Cougars got 'standard' 5.0 motors though.

I do know that in '85, they had a throttle body fuel injection (CFI) that looked a lot like a 2 barrel carburetor (at least on the Mustang). In '86, they switched to the 'flop hat' fuel injection system that was used until the 5.0 was discontinued. You can easily use a carburetor (and carb-type intake) on any 5.0, same as a 289 or 302. Or, if you feel comfortable with wiring and doing some plumbing, you can put in a high-pressure fuel injection pump, computer, and run the stock EEC IV fuel injection. Having done that to my '67 Cougar, I'm very familiar with the swap. On the upside, it runs very well with factory Ford EFI. I would use '89-93 for the sequential fuel delivery. My car got about 20-23 mpg, usually averaging 21 mpg on the highway. Good torque, smooth response. However, I never liked the aftermarket shock tower braces I had to run, and I've never seen a good one that could fit the big square EFI intake. Installing it required a lot of work, and I was never very satisfied with some of the choices I had to make.

If you want to run a newer 5.0 motor, I'd definitely get an HO, but I would also put on either a carburetor, or a throttle-body aftermarket EFI system like the Holley Sniper. Much less fuss, probably works better, and certainly looks a lot more appropriate in your engine bay.

Unless you get an Explorer/Mountaineer motor from the mid-90's-2001 (when the 5.0 was discontinued), I don't think it will be ODBII compliant. Making one of those EFI systems work would be a huge pain in the rear, and I don't think it would be worth the effort. You'd also need a distributor, since those later 5.0 HO motors used EDIS instead. The '98-01 heads on Mountaineers and Explorers are GT40P's, which are the best heads Ford ever put on a Windsor. Their only downside is that the revised spark plug angles make it hard to use most headers with them.


With the exception of the Lightning, all trucks, even your 2000, would've had the boring old E7TE heads and dished lower-compression pistons. Still a great, and incredibly reliable motor.
 

·
Registered
Joined
·
8,022 Posts
C5AE-6015E was a common 289 block from the Cleveland foundry used in literally millions of cars for model years '65-'67. I have two '66s in my garage with that block number. With some extra inspections it was even used in the HiPo engines of the same years. It could very well be the original block for your '67. The date code just above the block number will tell if its possibly an original block for your car. If they have not been machined away there should also be other date codes stamped on the block. In the photo below one of my blocks of that same casting number was cast on 21 Jan '66 and machined on 28 Jan '66. They were a hot seller and were machined and sold fairly quickly.

In the 60s Ford didn't make parts like engine blocks for a specific model application such as Fairlanes, Torinos or trucks. The casting number codes tell what sort of vehicle it was designed to go into but Ford used them in anything they wanted to. There was never a 289 block cast with a number indicating it should have gone into a Mustang but millions of Mustangs used 289 blocks. The early 289s were all designed for and intended to go into either Farilanes or full-sized Fords like the '66 289 Galaxie fastback I drove from '68 thru '77. As a starving student I never looked at that block closely, it may have had the same casting number as the ones I own today.
 

Attachments

·
Registered
Joined
·
425 Posts
+1 There were two Mustang "specific" blocks ( per casting number) , the '70 and '71 ('71 was referred to as "Service") Boss 302 blocks. These were the only blocks to use Z in the third position on the casting number. Remember this is "casting number" NOT "part number" used for ordering the part at a Ford dealer.
 

·
Registered
Joined
·
34 Posts
Hi all, very helpful information, thanks for the posts. Our '68 was my mom's daily driver in the early 70's so I'm almost positive it's original.


Would a compression check be enough to know if it's worth building on it as-is? There aren't any major taps or knocks.


Assuming the block stays put and the internals are left as-is, what bolt on options are there to give it a little more pep? Would a carb alone do that? Carb plus different heads?


The 5.0 HO options is attractive but which transmission is best if it's going to stay as an automatic? The original non-OD C4? I'd hope there something better since the C4 seems to need high RPM's to do much with it above 50mph.


Thanks for the great info! Looking forward to your replies.
Bart
 

·
Registered
Joined
·
2,355 Posts
Bart, doing a compression check would definitely reveal a lot about the engine's health. If it has good compression and it's not burning a ton of oil, I'd start with a good tuneup. Checking your hoses, plug wires, distributor and not changing a thing except worn or damaged parts is where I'd start.

With plug wires, just wrap one around your finger. It should be soft and supple. If you see cracks, or any tiny black spots where sparks have burned through the insulation, replace them all.

For hoses, just give 'em a squeeze. They should not feel crunchy, nor should they be ballooned out from the necks they're attached to. Ditto for vacuum hoses. Hoses are not too mysterious, but one thing people don't realize is that a normal rubber hose (for things like washer sprayers) is not the same as true vacuum hose. Vacuum hose has thicker walls that prevent it from collapsing under air pressure - so if you need to replace any of it, make sure you use actual vacuum hose.

For your distributor, pop the cap off (don't remove the wires unless you want to spend time figuring out the timing order!) and look at the inside of the cap, as well as the rotor. There will always be some wear, but hopefully you have brass contacts (aluminum ones don't last as long or work as well), and there is little corrosion. If the bug or cap look really blown up and eaten away with a lot of black streaks, that indicates arcing, and it'll kill power. It's time to replace. Then check your points. If they are blackened, you can try to simply clean them up by using some emery cloth, or even very fine grade sandpaper. Points are spring loaded, and they'll probably be closed. Just open them up with your fingers, put the material in between, and draw it through. You're not trying to remove metal, just get the carbon off them. I've even used a bit of shop towel in a pinch, but be careful not to leave any lint or fuzz in there. Once they are cleaner, take a look to see if they are nice, shiny, and flat. If they are pitted, or one side is cupped with the other forming a matching bump, they are shot and need to be replaced.

Then I'd do an oil change, and make SURE you use something with ZDDP to protect your flat-tappet cam.

Use a timing light and check your timing.

After all that, you've got a good starting point to begin making changes to improve performance.


Hop-ups for Windsors usually start with a good intake and carburetor, especially if you have a 2-barrel. If you already have a 4V carb, skip this bit. But with the old cast-iron 2V, you are at a big disadvantage. It's heavy as sin, and high up on the engine which hurts handling and slows you down, but it's also not that great for mix distribution. If your intention is a mild street build with crisp performance, the old Performer 289 is really hard to beat. If you want it a bit meaner, and have the hood clearance, an Edelbrock RPM Air-Gap or Weiand Stealth are both excellent choices. Amazingly, they should not kill your bottom end, but allow your engine to breathe well through any RPM range you are likely to use.

For a carburetor, choose one with annular boosters. They offer superior fuel atomization and metering, which means you get crisper throttle response, much better average power, and even good gas mileage. My favorite 4V carb for street use on a 302 is the Summit M-series 600 CFM. It's a descendant of the old Autolite 4100. They are reliable, easy to tune, deliver great power, and they're cheap. Hard to beat. The only other 'reasonably priced' carb with annular boosters besides the Summit carbs would probably be the Edelbrock AVS2. I'm not a fan of them, but in the interest of being nonpartisan, they do work, once they're set up right.

Windsors have pretty restrictive exhaust ports, so the next step to help them out is going to be headers. Keep in mind, your old cast-iron logs are quiet, tough, leak-free, and they fit really well, giving you lots of clearance. Headers are often a pain in the rear to get in. You will also have to change the rest of your exhaust system to fit them. If your car does not have dual exhaust yet, this is the time to correct that. For ease of fitment, and best performance, I would recommend 2 1/4" or 2 1/2". For mufflers, I really love Magnaflow. They are a straight-through design that offers virtually no restriction, but gives a smooth, mellow, mean-sounding exhaust note. Some people like chambered mufflers (Flowmaster for example) but while they are also very low restriction, I hate their sound. Glasspacks are both cheap and super low-restriction, but they are loud, and may cackle and drone, making highway use somewhat annoying. Turbo mufflers are quieter than the rest, and have good sound, but they are also a little more restrictive.

All of this info will apply equally (except for the bit about ZDDP) whether you keep your original engine, or put in a 5.0 HO motor - unless you choose to try and keep the stock Ford fuel injection system from a 5.0.

Very broadly speaking, with a setup like that and a stock cam, your engine will be somewhere between 200-235 horsepower at the rear tires. A stock 2V 289 or 302 could barely manage 150 net horsepower, and even the fuel-injected 5.0 engines (with E7 heads) only made about 225. Despite that number not sounding impressive, it will deliver plenty of tire smoke, grins, and good economy, with plenty of power from idle all the way to redline.

If you need more, you're going to have to have better heads. In stock form, your old 351 heads are not quite as good as a pair of cheap, junky E7's. But if you have them ported, they can be quite good - approaching GT40P flow numbers and delivering excellent performance. *ANY* aluminum head would deliver better performance, whether it's cheap Skip White NKB's, Edelbrock Performers, or the best but most expensive Ford street heads like AFR or Trick Flows.

In terms of transmission, the C4 is a pretty awesome unit. It's light, strong, easy to work on, and simple. If you're making 300 horsepower, and it's completely stock, it will burn up its friction materials pretty fast. After a rebuild, with modern clutch packs and a shift kit, it will be fine up to probably about 5-600 horsepower. Its top gear is 1:1, which means the RPMs your engine will run at on the highway are going to be limited by the gears in your rear differential. If you spend time out on the open road doing 80, then you are going to need to stick with something below 3.25:1 for mileage and economy. I run 2.80 highway gears in my Cougar, but she's a cruiser, not a drag racer. I can still spin the tires just fine, but she wouldn't beat too many modern cars in a stoplight grand prix. If you don't care about highway use, you could go with something steeper, like 3.75's, but it'll spin some serious RPMs out on the highway, slaughtering your mileage. Your engine can take the increased RPMs, even if your ears don't like them. That would make in-town use pretty exciting though!

If you really want to have wicked performance off the line, AND high-RPM economy, you'd want an overdrive transmission. They are bigger, heavier, more expensive. You'll definitely want to run 3.75 or even 4.10 rear gears with them, to take advantage of the overdrive. You'll need different transmission mounts, and a different (lightweight) driveshaft. The two automatics you could go with for overdrive are going to be the AOD, and the 4R70W. AOD has some compromises. It is fine for a cruiser. It has the same 3 gears as your C4, but adds a .66 overdrive to really cut down on highway RPMs. It is not known for crisp shifts, however, and full-throttle shifts to 3rd and 4th will eventually break things inside, without a major rework. You can get one already upgraded and reliable for something north of $2000. IMHO, the 4R70W is flat out better in every way. It is very closely related to the AOD, and most of the parts interchange. However, instead of hydraulic controls inside, they gutted it, and use electronics to shift the gears. It has a lower first and second gear than the C4 or AOD, and the same .66 overdrive as the AOD. You need to buy an electronic controller to run one, but it's as easy (or easier) to install than the TV cable an AOD requires to modulate shifts. Even a stock V6 Mustang 4R70W will handle any horsepower your Windsor can throw at it, without fuss, so a $300 junkyard special will work fine. The internals are very reliable. You'd want to get one from '98-01 for best results. After 2001, they stopped using a mechanical speedometer, so you have to do some fancy stuff to figure out how fast you're going. Shift quality is excellent with the 4R70W, partly because it offers asynchronous shifts. It doesn't have to wait for hydraulic fluid to fill and release two different gears at once to complete a shift - it just activates a solenoid, and BAM! The gear you want! Baumann Engineering produces the best controllers for them, and they allow you to control the shift firmness and shift points very simply, even allowing things like having a 'sport' and 'touring' mode if you took the time to set that up.

Personally, I'm a big fan of the C4. It's just a great little transmission, with zero fuss. Definitely one of the finest produced in the 60s, bar none.
 

·
Registered
Joined
·
34 Posts
Grimbrand, thanks for the very helpful post! I've been starting to work through the tune-up type of things, the cooling system is getting a complete update as soon as the parts get here and the rest will follow as I have time. I'll look into the intake manifold and carb as it gets warmer but should a stock 289 be able to spin the tires? Ours can't even with the crappy old tires that are on there at the moment.


Isn't there a tag on the differential with the gearing listed on it? I had it all out from under the car a couple of years ago but forget what was in there.
 

·
Registered
Joined
·
2,355 Posts
Well, I can't speak to all of them, but with 2.80s in the back, my old 289 didn't have the wheaties to spin the tires unless I had them in a puddle. They may have been rated at 200 horsepower, but a 2V 289 just does not produce too much torque. The *real* number was probably more like 150 or so.

There is a tag on the differential unless someone took it off, but you can also find out from your VIN which gears your car came with. 2.80s are very very common.

If you want to do a little math, with no account for frictional losses in the powertrain, your 289 (at peak health) makes 282 lb-ft of torque. In first gear, your C4 is giving you 2.46 multiplication of torque, so you're at 693 lb-ft. Then multiplied by the rear gears (2.80s), you're at 1942 pounds of tire-tickling power. While that may seem like a lot, in reality, with a bit of weight transfer onto the rear tires from acceleration, your contact patch with the ground is going to do an adequate job of providing traction.

A healthier, hot-rodded 302 putting out 350 lb-ft of torque, running through a 4R70W with 2.84 1st gear, and some 3.73 rear gears puts you at 3708 lb-ft. That'll melt some rubber into your wheelwells!

There's no 'magic number' that will tell you at what point the rear tires will begin to spin, because it's all dynamic; your torque converter, weather, weight transfer and many other factors come in to play. You also have to realize that your car's not actually at its peak torque while you're at your stock torque converter's 1600-1800 RPM stall - maybe only putting out 200 lb-ft. But it does give you some idea of the math involved, and some ways you can get better acceleration.

It's important to note that gearing isn't really the end-all-beat-all for driving too. Out on the highway, my car has a great passing gear, and despite running 2.80s with a C4, when I step on it to pass someone on a 2-lane blacktop at 55 mph, my 2nd gear acceleration is easily as good or better than a similar Cougar would be, running a heavy overdrive transmission. That's because their gear ratios would drop down to 3rd, not 2nd. If we figure a 289 like yours, making 282 lb-ft of torque, in 2nd gear with a C4 (1.46 gear) and 2.80s, you are getting 1153 lbs of get-up-and-go. Against a car with an AOD, in 3rd, they're at 1:1 (so no multiplier) and 3.73 rear gears (very common for an OD transmission), which works out to be 1,052 lb-ft.

Once you add in the extra weight of the AOD, and account for the extra 25-30 lb-ft of torque it's stealing (because the AOD is a power-hungry beast anyway), you'd be pulling away easy.

Bottom line here? The old C4 is a lightweight, cheap, simple, buttkicking machine. Maybe not quite as versatile as an AOD (or its younger, leaner, better cousin, the 4R70W), but still very worth using. Making more tire smoke takes either more power, or more compromises with your driveline.
 

·
Registered
Joined
·
34 Posts
Spinning the tires isn't really necessary but if you told me it should do it easily, but it doesn't, it might be another sign that the insides aren't too good.

Thanks for all of the information, very helpful!
 

·
Registered
Joined
·
34 Posts
Grimbrand, forgot to ask, do the valves need to be adjusted with these engines/heads?
Thanks
 
1 - 20 of 27 Posts
Top