im thinking about picking up a06-08 GT for my DD.

how far can i push the HP/TQ before i need to upgrade my trans / internals?

id like 500-600 hp some day.

 

It'll do 500-550 right now.

 

well if your lucky it may hold together for 500-550 HP. That would be with some luck. The 5/8" input shaft is the weakest point to any high power outputs. Third gear is a common failure point when pushing these trannies.
Mine broke at about 450 HP but that was just mine. I have seen several break at the same level though. My mantra is dont fix it if it aint broken anyways.

 

hmm so to safely run 500-600 what would i need to upgrade?

 

If you're spending the kind of money to get your car up to 500-600hp, you might as well spend the money to modify the transmission/driveline as well. Hypothetically you would have already spend up to seven grand as it is, (turbo/blower kit, exhaust, etc)

 

Does anyone know how much the new TCI Tranny is? Or even the rebuild kit?

 

Are you guys talking 500-550 RWHP or flywheel? Big 20% difference with an auto.

 

I'd like to know how much the TCI tranny is also.

 

They're rated that at the fly.

 

Call Brenspeed and ask him. I was told by a member on here that hes blown up an auto trans on one ofhis shop cars, because of too much boost.