C-4 ????s
 

I have a 65 stang with C-4 tranny. I'm not sure how c-4s, in stock form, generally perform, but mine shifts from 1st to 2nd gear almost immediately after taking off, and then shifts from 2nd to 3rd gear somewhere around 30-35 mph. To me it seems as though the shift points should come a little later as that would help catch engine at better rpms. Is it common for C-4s to be geared this way? What can I do to change this without any major modifications (in other words, is there some valve or something that can adjust this, might be dumb question, but i gotta ask)? Finally, what modifications are there that can be done (shift kits, gearing, rearend)? I plan on tuning my engine to about 350 hp when completely done, might go little higher, no more than 380 hp completely streetable with low end being my target. Thanks for any help.

Sleeperstang <-----I know, 380 hp might not let it be a sleeper no more:)

P.S. By the way, my budget could go as high as $350 for any tranny modifications, I do plan on putting a T-5 at a later time.

well, i had a c-4 built for my car, drove that for a year, and then went to a 5 speed. after launch, when i floored it, it would shift from 1 to 2 somewhere around 20 mph. then it would shift into third at around 65. when i had the tranny built, they beefed it up a little, and threw in a shift kit. the gearing was not touched. either you have a problem, or the tranny has been altered. I don't know this, but maybe ford made a c-4 with different gearing? i don't know if they did or didn't, but mine was different from yours.

Don't know about your gearing or shifting points, but the c4 built prior to 1970 was a notoriously weak. If I was going to build a motor, I would have the tranny built to handle it (c4 can be built very tough) and put in the desired shift kit at that point.

TRY AN ADJUSTABLE VACUME MODULATOR
VALVE AROUND $25.00 FROM LOCAL PARTS
STORES MOST AFTERMARKET VALVES ARE
USUALLY ADJUSTABLE.YOU ONLY NEED
A POCKET SCREWDRIVER.I WOULD ALSO
GET A SHIFT KIT INSTALLED. AND THEN
GET A CONVERTER PROB AROUND 2800
RPM FOR ALMOST STOCK.

One way to control the shift points on a C4 is to install a manual valve body. It will stay in the gear you select until you hit the shifter. Might be something to consider when you do the rebuild. They come in both the normal pattern as well as reverse pattern, where 1st gear is the top position, for 2nd down one and 3rd down one more. It does take a while to use to, but it works great. Ad a shift light and you got it made.

Ron

Ron is right as usual, but you do lose any automatic shifting functions with the manual valve body.

Rev

Now Rev...now I need to fitted for a larger helmet...nice thing about these forums, when you do make a mistake there are others who can correct you when you are wrong, and you learn from it. There is a TON of knowledge here.

Ron