a few question

i have a few questions while my truck is unthawing lol

what can i do to help. i have a 91 5 speed, but at 80 in 5th i know i have more power still but its screamin at 4000 anything i can do to change that? diffrent tranny? diffrent rear end? what would i need?
thanks
mike

You have a few options - but no easy fix. There are no different gears for the Mazda rearend. But, a RX7 differential does bolt in but you have to shorten the drive shaft. Certian year Mazda RX7's have a little better 5th gear, but you will have to find one, tear the trans apart to get the gear, then tear your trans apart to install it. Or go with taller tires which would be the easy option, but not necessilary what you WANT to do.

Best of luck.