Depends on the GTO. I beat several at the strip when stock but most were the 5.7. The SRT automatic transmission is a bit slow to change. Lot's of things happen during the shifts. Timing is pulled, the throttle body partially closes and the supercharger disengages. So needless to say, softish. The transmission is strong. Keep the fluid (correct fluid) at the correct level and it can really take a beating with no negative effects.

Les