im going to build a mild 351w formy '73 project and would like to run a C4, at least for the time being, but i was wondering what it would take to make my C4 hold up to the extra amount of torque? what is everyone else running?
A mild 351 like mine puts out 400 ft lbs of torque and 350 hp. You can use a stock V-8 C4 with a TransGo -2 shift kit. That is 5 clutches in the forward pack and 4 clutches in the direct pack. Stock friction surfaces and "F" fluid. An auxillary cooler rated at 20000 lbs GVW should be added to keep temps down. This will handle all your street driving and some trips to the drag strip. If you plan on racing more often, then 5 clutches in both packs with stock friction materials and the same shift kit will give you good service for 10 to 20 years if you service it each two years. If you add the largest cooler you can find, about 30000 lbs GVW it will extend the life that much more. You should consider adding positive oiling to the #9 thrust washer. It takes the entire thrust load under acceleration. They have a habit of tearing the lugs off and spinning on the case - ruining the case and the transmission. One note here; if you use "racing" friction materials they will not hold up as well as stock friction materials on the street.
Thanks for the info. this will be a street engine with just a few trips a year to the track for some weekend fun.
Thanks Wagesofsin, I appreciate the good words. Mean maverick, I don't really do C4s for the money. If I did I would be shipping them all over the lower forty-eight. I build C4s for friends. My friends deserve the best and I am in a position where I can give them that at a very affordable price. The "stock" rebuild that I do will support a 400 HP engine and run for an expected 20 years with only periodic maintenance. (servicing every two years - adjusting bands and new fluid) I have a few friends who abuse the trannies but that's all part of the game. I really don't make much money on the transmissions that I build because of the machine work and parts costs. I have enough income to live on so I don't need the money. Your transmission would only cost $800. The problem comes if you have problems with it. A friend can bring the tranny to me and I can disassemble it and find the cause of the problem. Then I can build it up to keep that from happening again. If it is my fault or bad parts I build it up for free, if it is their fault then they pay for it. Never any discussion of warrantee because we trust each other. If I put a written warranty on my transmissions it would be for ten years for street transmissions and five years for racing transmissions. That is what I expect under the worst conditions. It would also require two year servicing. As it is, I know that people ignore changing oil and adjusting bands - I make as much allowance for that as I can. I haven't had one returned for premature failure in quite a few years. Makes you wish we were neighbors don't it?
yeah, that would be awesome. i have a friend that is familiar with these transmission so the next time i see him ill run this by him and see what it'll cost me
