I have a 1988 Formula Firebird with a 305 mated to a T5 transmission. From what I understand reading the stickies this is a World Class T5 rated for 300 lb/ft tq. The drivetrain currently has 180k on it and is holding but under heavy acceleration I can smell burning oil (may be the trans, may be a leak hitting the headers). It also "grabs" the gears a little shifting into 5th.

I have acquired a L31 350 Vortec motor and am looking to swap it in. My question is this. Should I rebuild my current transmission, or should I spend the much larger sum for a bullet proof TKO or t56? Can the factory T5 be rebuilt in such a way that it can handle the 330+ lb/ft produced by the L31? What does this incorporate and what would I be looking to spend?

If the verdict is I will absolutely need a better transmission, I plan to just pull the current motor and slap the 350 in until it blows my factory unit up. Otherwise I will pull the entire train and get the transmission rebuilt before i replace it.

Thanks for any input I may recieve.

 

Guess it depends mostly on how you drive it and if you plan to take it to the track. If your not to crazy you probably could just keep the t-5 in there and rebuild it once it breaks. The t-56 comes with it's own mess of problems and can get expensive if you go that route.

 

Well it IS going to be my fun toy car, so it wont see many miles, but the miles I put on it will probably be pretty rough. Is there any way to make the guts in my stock unit tougher?

 

Yeah there is http://www.gforcetransmissions.com/tran_gt-5.asp but your still dealing with a weak case.

 

I'm not too concerned about the case itself. In all likelihood I wont ever be running over 300hp through it.