what gear are you running now? The reason I ask is because mine has a 3.73 it really does not hook worth a crap even with drag radials. My 01 Gt with a kenne bell had a 3.27 with the 5 speed and that was a pretty good set up. In my 65 ac cobra I went from 3.27 to 3.73 and really didn't notice that much of a difference so Its hard to tell.
I have factory 3.55's
Just my two cents but one gear range one way or another will not make much difference. Therefore the next question is to find out what exactly he is running in regards to gears and transmission. I would hate to see you dump money into it and not get the kind of change you are looking for.
Looking at those I don't see a dramatic difference. Its hard to tell if you will notice much of a change. A lot of determining what is the best gearing setup is the type of tire, tire size, driving habbits and engine power band etc.. What are you trying to improve upon?
I think you may have a difficult time trying to get the driving characteristics of a cobra to match that of a z06.
LS6/M12
1st Gear2.97:1
2nd Gear2.07:1
3rd Gear1.43:1
4th Gear1.00:1
5th Gear0.84:1
6th Gear0.56:1
Reverse3.28:1
Axle Ratio 3.42:1
Final Drive Ratio 1.91:1
I've got a custom 32 spline main T56 using the GM carbon triple cone synchros 1st-4th, upgraded everything. It's in an NA 01 with 3.55's. with 26.3" R888 305's 5th gear tops out at 190 @ 7,200 rpm's. It's built for an F1A thats yet to go on the car. The shifts drop the RPM's to 5,000 on all but 5th, where it drops you to 6k when punching out of gears at 7,200. Perfect for a PSR cammed NA car or centri car. If you have any questions, let me know.
Is it possible to have a t56 re geared so the 4th gear is faster than 140 , because 5-6 are over drives and it builds way way too much heat
Not to my knowledge without a complete custom gear set that I don't think anyone would make. Not worth it at all. You can lower the numerical value of the diff, increase rear tire diameter or rev higher before you shift.
As for the building too much heat in 5th and 6th. You can certainly run 5th out (horsepower limited) without too much fear of butting the rings. 6th, on a stock engine is a no no though, as you stated. However, you can have a larger ring gap set on a rebuilt engine for long high power high speed pulls under a lot of load.
After my last engine that's what we did
.20 over and I have yet to do any top end pulls, but I'm rather hesitant of doing so
What were the ring gaps set at?