ok i have a 93 firebird formula that has a lot of miles and the tranny and engine was rebuilt.....ok so the car shift fine in normal everyday driving but when u start to get on it it acts up and wont shift right, and when it warms up and it hit that rev limter a good 5 times then shift, and idk but my car is slow as hell and wont even squal a tire, i think the tranny is robbing my power but idk so what do i do???????????............oh and i was wanting to put 4.10 gears in my car soon, do u think that this is a bad idea from u have heard so far?

 

First of all check the fluid condition... is it bright red, like kool-aid or is it dark and smells bad like it is burnt? Is the fluid level correct?

I suspect your new engine has knocked out the transmission. Gear changes are not a problem if the gear ratio you have chosen suits your needs... definately look after the transmission 1st though.

g