How much HP will a C4 hold?

pdw5000

New Member
May 25, 2008
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I am building a 408W that is going to be making around 500-600hp. I have a rebuilt 68 C4, 26 spline tranny with high performance clutches and a B&M shift kit. My engine builder tells me that pre 1970 C4's are junk and I need to get a 70's C4 to handle the power because of the bigger input shaft. Is this necessary?
 
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Yup, its all about what you want to spend.

If your going new, Id go the Performance Auto route and get the lifetime warrenty with it. They do rate them at 1000hp for the super comp. (Dunno if I would put that much to one) Its what a few here run, and what I just bought for my car. Big thing, have a good trans cooler though, heat is probably the #1 reason they fail.
 
I am just thinking about buying a junk 70 era C4 and rebuilding it. I imagine that's basically what P.A. , B&M, etc. are.
:lol:
NO!!!! Just rebuilding a junkyard c4 aint going to cut it if your making 500 lb ft of torque. Check out Performance auto and they list the mods they do to there trannys. Way beyond what most can do in there own garage, and most of the parts they use are not stock c4 parts. Do some research on this or you will be sorry when your tranny goes BOOM!!
ken
 
ya no kidding. You could do it yourself it you have the knowledge though. There are a couple ppl that buy the parts from PA and do their own, so you would end up with the same trans.

BUT, by the time you get those parts, do the time to put them in, how much are you going to save, and now you have no warrenty. PA is LIFETIME. Peace of mind, break it. Pay the shipping and have it like brand new again.
 
Built mine from a 70 trans. PA input shaft, stock A servo, transbrake valve body. I have freshend it up once. That was pretty much because the first time I built it, I didn't know the HP I would be making 3 years down the road. So I finally burned up the forward clutches I was cheap on at first. Now I've upgraded to Alto reds, and I'm still beating on it with 13psi from a turbo.
 
a properly built C4 can handle as much as 800hp, though i wouldnt put that much power through one on a regular basis unless i had a strict maintenance program, including freshening up the trans at least once during the race season.

my recommendation would be to contact lentech automatics and get one of their terminator AOD's with a full pressure valve body. these transmission will handle the power of your windsor easily, and give you an overdrive to boot.
 
I can't find a web site for "Performance Auto transmissions" - they have an annoyingly generic name. The first hits on Google are TCI and Campbell... does anyone have a link?
 
If you are going to build a hot windsor and want a 3spd . . . turbo 400 is the way to go.

If you have your heart set on a c4 . . . dynamic mighty mite.

Seen 4-5 cars trap 115-125 in the 1/8 with them.
Any c4/AOD will have to be rebuilt yearly at 600-700 flywheel if you race it hard/often.
 
Dustin, how many forward clutches in the first build? Second build? How many in the direct?
Sorry, computer is F'ed. One steel and clutch extra. The only reason the cheap clutches went was I put it in third and foot braked it to see when it spooled before I had a trans-brake. The direct clutches looked brand new.
If you are thinking about building your own, talk to Jay at Broaderperformance.com
Only does Fords, know his stuff. Can send you hard parts already machined.