how much hp is safe to still keep the stock 6-speed? besides for putting a better clutch in will the rest be ok?

 

should reliably hold up to 450hp I believe, it all depends how you drive though, high rpm clutch dumps will always destroy clutches/trannys/rearends really quick.

Depends upon on too many variables...

 

yeah very true all fourth gens are a t-56 correct?

 

The only manual offered in the 4th gens is the t56, yes.

 

The T-56s are a different animal from the autos, put in the better clutch as planned and you should have nothing to worry about.

 

worry about the rear, thats whats going to break

 

Yeah, a friend refused to do the A4 right and after letting a local hack screw it up repeatedly he put a T56 in it, within a couple months the rear was shot and he never even put the ET streets on it.

Wheelhop or a hard hook on slick both break the 7.5" when it is behind a manual, the auto delivers less shock so it is a little easier on it.

 

what rear you running?

 

he has a B body it has an 8.5 rear

 

Yeah the LT1 b-body got a 10-bolt 8.5" 30 spline which is comparable to a 12 bolt, the old 28 spline 8.5" was a little weaker but they ended those in the late 80s. Some civilian L99 cars got 7.5" axles, open diff keeps them alive behind the baby motor.

The 8.5" can run 9s with an automatic, have seen guys start breaking it running slower on the T56 which is a fairly popular mod.