sflip09

The back story is that I'm swapping a C4 for a T5 in my 66 with a 289. The T5 is used and I want to make sure the gear ratio in the T5 will work for me without swapping my rear. I looked for some websites to do the formula but couldn't find any. Any idea of the ideal ratio for 1st gear thru 5th?

My rear differential is a 3.25 and I'm running 225 60x15

One last question: I have a friend who is willing to give me is T5 from a Chevy. I know I'll need to replace the output shaft and use a bell housing adapter. Anything I'd have to do?

Thanks for any help.

imp

C4 has 3 gear ratios, 1st, 2nd. and 3rd., which is "high-gear", 1:1. T5 has 4 gear ratios AND a 5th. which is overdriven. Given that the gear ratios in either transmission are quite similar, from 1st. to 4th. (T-5 4th. is 1:1), and that Fox Mustangs equipped with 5.0 HO engines used T-5s along with 3.08 rear gear ratios, 3.25 will probably work well with a T-5.

What kind of formulas are you looking for? Speedometer gearing? Rear axle gear ratio is a matter of personal choice, depending on what is being looked for: quick acceleration or good road fuel economy. imp

sflip09

imp,
Thanks for getting back to me so quickly. The formula I'm looking for is to see the best great ratio for 1st, 2nd, 3rd... My understanding is that you can chose the ratio when rebuilding a trans.