How much horsepower can a stock Trans-Am engine handle?

Question

i have a 1979 Trans-am with a 6.6L V8 engine. how much horse power can it handle till it blows up?

Answer 1

I threw some 1970 Pontiac Grand Prix 10.25:1 350 HP (horse power) heads on a 1978 400 cid/ 6.6 liter High Output engine that had factory 8:1 compression heads. The 1970 heads could seal 210 PSI compression, the 1978 heads were 150 PSI compression, the compression rings were 150 PSI factory in the 1978 block. Every six months I would do a compression test, it was always @ 150 PSI after I put on the 210 PSI/ 10.25:1 heads. It worked great, and did that car ever fly, what a difference 0-60 MPH time decreased by 2.5 seconds compared to when I had the 8:1 heads on the 1970 GP. That engine did handle the extra Horse Power! The only problem if you have a 1978-1979 turbo- hydromatic 400 factory I think it only has 5 set clutch pack, the 1970 TH-40 (turbo-hydramatic 400) has the 7 set clutch pack to handle the horse power, and I had a 12 Bolt heavy duty rear end in my Pontiac. You might want to modify your tranny either manual or standard. 10 bolt Trans Am rear end, I believe POSI, should handle the power! My other 1970 Pontiac Grand Prix J had a GTO 400 engine 350 HP, with 10 bolt rear end, handled the power.