To build an engine with a bit more power some head work and custom camshaft grind and intake modications is needed. Today's limiting factor is the crap gasoline we have so have to use a dish piston and drop compression ratio unless race gas is available. Back in the day we could get good quality 93 octane gas and run 72 cc or less heads and flat top pistons and not have to worry about detonation. Friend had a good running 400 factory cam with TRW flat tops with stock #48 heads that ran fine on sunoco 93. Car would run 12.00 -12.20 all day.
Have you seen the ram air 2 first Gen birds that run in the FAST (factory appearing stock tire). Pretty impressive cars.