The c4 trans im using on my 302 is from a 250 engine. I also used the 250 convertor. Question is.... It shifts way to fast before rpms get up unless put my foot in it. Manual shifting is fine as i can draw it out more without flooring it. It shifts exactly like it did with the 250. Thats fine... But im wondering since ive read that most all c4s are the same why is it that in my dads 69 fairlane the gears seemed to be more spread out in ratio vs this one? It had the same rear gears of 2.79 and im assuming the same ratio trans. Maybe tthis is the reason?
There should be a small screw inside the vacuum connection of the modulator valve(assuming single port pointed to rear of car).. Turning it clockwise will delay and firm shifts. Try a turn at a time till you find the "sweet spot", too much will prevent trans from shifting at all.
