Looking for info on 74-78 C4 trans for swapping

Eli McCrae

New Member
May 9, 2019
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Indiana
I have a 98 Ranger that I'm doing a V8 swap with. Looking for information on using the 74-78 302 V8 trans, with its 143-tooth flywheel.

This will give me better header clearance. Done some research and found that this application's trans is too weak.

Has anyone had the input shaft heat treated successfully for increased strength? Or, had a shaft custom made?

I know there will be doubters about this interest, but I like a good challenge for a build. :) Hoping someone has some helpful suggestions.

Am anticipating finding an older 'Stang to build someday. Will be gathering info on that as well while I'm here.
 
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Hummmmm, where to go with this :thinking:
are you talking about the C4 trans?

Yep, the C4 automatic transmission that was used behind the 302 in the 1974-1978 Mustang II.

I Have found that with the smaller transmission case, flexplate (143 tooth), etc, using it in a V8 Ranger swap will allow more room for full-length tube headers.
Has been done before...But I have also read that this version of the C4 transmissions are weak (particularly the input shaft). And possibly other internal parts.

Wondering if anyone here may have some info, one way or the other, on this particular application. I might be interested in having the internals hardened, or getting stronger aftermarket components. I have seen reference to this, but not much info, so I was hoping someone in a Mustang forum might be of some help with information or advice.

Surely someone has some experience with beefing up this type of transmission in the V8 Mustangs. I went to school with a couple of guys back in the day who ran these Cobras and modified them, however I've lost contact with then over the last 35 years...lol
 
Isn't Art Carr transmissions the only one to have a higher stall converter for and a 50oz imbalance 141 tooth flex plate for m2 these days?
Might be the guy to talk to about it.
 
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I don't know what's too weak about it, I run 12s with mine on drag radials and don't have problems with it. I have a manual valve body and TCI converter in it, that's it.
 
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Isn't Art Carr transmissions the only one to have a higher stall converter for and a 50oz imbalance 141 tooth flex plate for m2 these days?
Might be the guy to talk to about it.
Art Carr has the flexplate (I still have one from the engine swap I never did), and TCI makes a converter.
 
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Hello Eli and welcome to the site! :)

As for the C4 being weak in the II, I don't think that's necessarily the case. To the best of my knowledge the only thing that was changed for them to be installed in a II was the bell housing and the corresponding flex plate and converter. Otherwise, the transmission is the same as what was installed in other cars and trucks from that era. So, ultimately, you really only need the bell, flex plate, and a converter to make it work for a Ranger swap. Now, given that you're looking for a II specific part, they aren't too cheap or easy to come by. I think locating the bell housing will be your biggest hurdle, otherwise you can pick up a C4 out of pretty much anything and make it work for your application. I also think that whoever was giving you this "information" that these transmissions are weaker than other C4s are basically parroting that the Mustang II is weak, that they are junk, or whatever other bias that a lot of people like to share that look down their noses on the II. Unless they are confusing the C4 with the RAD 4 speed, they are mistaken. So, grab a C4 from whatever, look for a Mustang II bell housing, you can order the Art Carr flex plate or find a stock piece, find a suitable converter, and build the transmission to match your combo and you're golden.
 
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