with cams, stock heads, and most other boltons, a friend put down 261 WHP/315 tq after tune..
With a cobra crank, some lightweight internals, the fox lake lower intake, valves and such he bumped that up to 305/321... at the wheels, so there's some potential but without head work there's not terribly much, and boost is the way to go for most power... (or nitrous but that's more limited in how long you can use it haha)