good info guys. shifting into 4th was something i was trying to get away from. i've always had just a little better than stock rebuilds. i think next time i'll fork out the money, especially if 4th gear can take a beating too. i was going to throw my 3.23's back in so i know i would stay in 3rd at the end, but i was thinking maybe i could just hold it out in 3rd if i locked it up. I didnt really want to change tire size much either only because im keeping the tires on my z06 wheels and dont want them to look huge on them. our dyno day got moved to this saturday (the 1st), so i'll probably be at the track within a few weeks or so to test this theory out

 

LT-x7 "My street car gains 3-4mph n/a and 15-16mph on a 150 shot shifting into 4th in the 1/4. But I think I could run faster n/a if I could finish in 3rd, I can't really pull 4th on motor. Hopefully next time out I'll be on taller tires that will provide that little bit of extra gear to let me finish in 3rd n/a."
If you are gaining this much in the 1/4 mile, you are pulling fourth on the motor, and that is great. Most drivers have the vehicle geared so they use the first three gears only in the 1/4 mile. Nothing wrong with you doing it this way, as there could be an improvement in ET & speed as your case proves. As long as the 3-4 WOT shift is a quick shift, you should not have any problems with band life, if not, there are a couple ways to address it.

 

I wouldn't mind having it geared to use just the first three gears but until I change over to a rear end other than the Mazda rear my gear choices are 4.10's or 4.10's. Or maybe I'll just build a motor to spin 7000rpm.

 

are there any transmission tables that would help quicken the 3-4 shift or is it just the case that it needs to be a good tranny build to handle it?