C-4 vs C-6

Ok guys so I have a bit of a dilemma, my new build will make about 625 hP and about the same on torque. I want a trans that will hold together on the street with some runs down the quarter. I'm planing on running 3.55 or 3.73 gears in the car. I'd love to put the c6 in the car but weight is a huge concern to me right now I'm fighting for every pound I can take off the car.

I have a C4 core I think it's the earlier 70 and before pan fill job. Can it be changed to the later larger input shaft? What do I need to do to get this thing to live becides an OMFG sized trans cooler?

Or should I just find a c6 and run it?

I have some stall converters for a c4 so that cuts some build costs and my cars currently configured for a c4. Should I just stick with that?????

Can you guys tell I'm confused and gone crazy due to snow?

billet input shaft, brazed forward drum, rollerized 3 pinion forward planet, good vb, deep pan, teflon pump rings , good int servo & kevlar band, 6 clutches in each drum.....................c4 be good to go.................nice big cooler is a must.

I figured on the cooler. Where can I find all these parts at?

richter69 wrote:billet input shaft, brazed forward drum, rollerized 3 pinion forward planet, good vb, deep pan, teflon pump rings , good int servo & kevlar band, 6 clutches in each drum.....................c4 be good to go.................nice big cooler is a must.

X2
For the parts : Harold and J.R at Dynamic Racing Transmissions, Jay At Broader Performance and PTC in Alabama.
B&M Stack style cooler with fan and either braided or Russells blue hose with the twist lock fittings.

Sounds good got more questions lol.

How do I tell what year my trans is? Will the later parts interchange with the earlier 60's trans?

You need to run a 70 and up c-4 case which should have 26 spline input shaft.

Well this trans has snapped the stator shaft and the input is missing?? Came out of my 73 but idk if that's the original C-4 or not

Does it have the little breather cap on top of the extension housing? The date code is cast in just behind the shift linkage

No cap on top. Things so caked in crap I can't see casting number

Matt, do the C6 its much cheaper and more durable. The extra little bit of weight isn't the end of the world.

dfree383 wrote:Matt, do the C6 its much cheaper and more durable. The extra little bit of weight isn't the end of the world.

X2

I think I'll go that route. Seeing as how I have a not so good c4 case. What can I do to make that c6 require less power to run?

Stop worrying about it and get it running........... Your money is uch better spent on a good convertor, Gears, A few additional parts for your motor, Ect.

Matt, I don't think the c6 needs anything to worry about. I did before I built mine but I now believe in isn't worth the thought. Now mine is built with all the good stuff. I was running 6.50's leaving at 2,000 rpms on a flat tappet cam with a tunnel ram. The thing to think is I am only about 4 to 5 tenths slower than most full bracket big blocks with glides, gears, roller cams and 5,000+ converters. I do more street running than anything. I love my C6. I also know it will last more than a C4. Talk to Mike Whitefield on here. He did mine, and a really good job at that.

I just want to get it done right the first time through, I may not have time for a second go around.

dfree383 wrote:Stop worrying about it and get it running........... Your money is uch better spent on a good convertor, Gears, A few additional parts for your motor, Ect.

Another vote! Back when I first got into the 385 world I picked up my C6 before I had a motor. Not having a pot to piss in I tore it down myself, got a TCI rebuild kit, B&M valvebody kit, and went to town. The only trouble I've ever had was in the beginning when I managed to forget to torque down the valvebody

I'll never forget how I giggled like a school girl when the car would haze the tires going into third at 70 with my mostly stock 429 (truck convertor too) My C6 has always shifted awesome & never given me any trouble. Watching runs on Youtube it's amazing how many lazy-shifting setups you see, when it's so easy to make these trannys awesome.

Maddmattmustangs wrote:I just want to get it done right the first time through, I may not have time for a second go around.

Its got to go down the track before you can break it.......

Ouch dfree

Way Fast Whitey FTW...

Tennessee Bullitt wrote:Matt, I don't think the c6 needs anything to worry about. I did before I built mine but I now believe in isn't worth the thought. Now mine is built with all the good stuff. I was running 6.50's leaving at 2,000 rpms on a flat tappet cam with a tunnel ram. The thing to think is I am only about 4 to 5 tenths slower than most full bracket big blocks with glides, gears, roller cams and 5,000+ converters. I do more street running than anything. I love my C6. I also know it will last more than a C4. Talk to Mike Whitefield on here. He did mine, and a really good job at that.

Mike's the guy to talk to here.

dfree383 wrote:Matt, do the C6 its much cheaper and more durable. The extra little bit of weight isn't the end of the world.

I agree with Dave.

Now...if it was a track only car, the C-4 might be a wiser choice.

Here is a thread I go to to get research info on C-4 transmissions :

http://www.fordmuscleforums.com/c4-transmissions/416584-monster-c4-thread-text-edited-way-long-version2.html