Hello,

I was curious how well a C6 transmission from a 1983 Ford with a 302 would meet up with a 302 from a 1980 Ford?? I've heard some people talk about bolt patterns of a C6 not matching but I thought that the only way bolt patterns wouldn't match is if the C6 tranny was a big block C6.

Any ideas on this? I appreciate all the help!

Jon Preston

 

Yep, your good to go!


Any C6 from a 300-6cyl, 302 and 351 will all interchange to one another. That is the small block patern.

Then theres the big block patern, 400, 429 and 460.

And the FE block patern, 360/390.

And finally the Diesel patern, witch is unique to only diesels.

 

Sounds good!! Thank you!

 

If you have a 4x4, the small pattern c6's are very common. If you have a 2wd, then the small pattern c6 is not very common, and used to be snapped up by people racing 302's, though that was a long time ago and they probably use something else now, or beef up a c4 to do the same thing.

 

If you can scare up a 351C 4bbl torque converter or possibly one from a 351HO than you will gain a bit. I had that setup in a 1970 1/2 Falcon Wagon (Torino/Fairlane 500 body) behind a 302 with 289 4V heads, 351W exhaust manifolds and dual exhausts. Excellent combination.

 

I know you meant 351W in the above, but it can be confusing to the uninitiated. There was the 351M which had the "big block pattern" and should be listed with the 400, 429, 460.

 

Thanks for all of your input guys! I really appreciate the help!

Jon Preston

 

So,

What is the proper procedure for attaching the c6 to the 302 and flexplate?

 

Jon

The blockplate is first put in position, then the flexplate bolts to the crankshaft - it will only fit in one position as the bolt holes are deliberately spaced unevenly.
You need the flexplate that matches your engine & year........sometime in 1981 302's went from a 28oz to a 50oz inbalance.
If you don't have one already, you also need an auto-trans starter........manual starters have a different pinion reach.

The snout of the torque converter fits into the hole in the crankshaft (like a manual trans pilot) but not all converters have the same size pilot, so check for a match.

The torque converter needs to be installed into the trans carefully. There are two splined shafts, & the pump drive.......all three MUST engage properly or major damage occurs on startup.

By playing with it on the floor, before you lift it up to the engine, you can get familiar with it.
Partially prefill the converter with 2-3 quarts of fluid & slip it onto the input shaft (the first set of splines).
Turning it, without too much backward pressure, it will engage onto the second splines (you need to feel this happen); then, with more rotating, it will lastly engage the pump drive (again, you need to feel this happen).
By taking note of the converter position at this stage, you will be able to notice if it shifts in the process of lifting it up to the motor, & correct it.

The trans is then lifted up & slid into place.
I think I've used two guide pins (bolts with the heads removed) screwed into the block, to make this easier - I know I have with manual transmissions; I also put some grease on the converter pilot to help it slide in.
Take care that the 4x studs on the converter line up & engage the flexplate holes.
Some flexplates also have four holes to line up with the converter drain plug, regardless of it's position; but some only have one, in which case it needs to be turned to position.
The trans can then be bolted up to the block - one of these bolts also secures the dipstick tube.
With the trans bolted tight, but while the 4x converter nuts are still off, the converter should be free to move forward & aft slightly, with little resistance.
Turning the motor by hand, the nuts can then be installed on the converter studs.

If anything feels 'wrong' during this stage, resist the temptation to just pull it together with the bolts - back the trans out & recheck, particularly regarding the converter engagement.

From there - converter access cover back on, rear cross member & mount, shifter & kickdown linkages, 3/16" vacuum line to the modulator, cooler lines, NSS & reverse light wiring, starter, speedo cable, driveshaft & fluid.

I think that's everything - take it for a spin, check the fluid level &, if necessary, adjust the modulator

 

That sounds awesome and was exactly what I was needing! I have purchased my c6 and I knew somewhat how to go about it, but not completely 100% on how it all went together.

Thank you for your information!

Jon Preston

 

One item, the top left bolt (viewed from the front, it will be the top right from underneath) holds the vacuum tube for the modulator. It is a good practice, if you don't have the plastic vacuum "tee" on the firewall, to have a loop in the hose that raises it up a bit between the manifold fitting and the tube. This prevents fuel from condensing in the tube and running down to the modulator.

 

Ken - Reps to you for that well-explained post.

 

Same here, real good job on the Torque converter instructions.

 

I will bring this out so you see it again. I made this mistake a long time ago, I had a flexplate with only 1 big hole for the drain plug. I didn't know about it at the time and didn't see it. I bolted the torque converter up, and when I went to start it, it sounded terrible but it started. I got under there and looked, and the flexplate was wobbling around, I had bolted the thing up, and it was bent over the plug in the torque converter.

I loosened it up and got it re-positioned, and it's running to this day, but the starter never has sounded very good since then. I think it damaged some of the teeth on the flexplate, since it's had a different starter in it over the years. It was in a old 65 mustang I have.

 

Good luck with the swap! I'm running a 302/C6 combo myself. It sounds like you've got everything figured out but I wanted to reiterate that it is very important to get the correct flexplate for your motor. Luckily they are still easy to find! I bought a new flexplate for mine and it came with torque converter drain holes in 4 spots.