im running a 408 that's 500hp and 540 ft lb at 4000 rpm
Its also got a 4000 converter , and although probably too low , im running 3.23 gears.
Its a street car that has a run at the strip occasionally , will still do a 1.6 60 ft with 26'' tyres .
I've had 3.9's in it but couldn't stand the high...