Let us know what the rules are. Back in the late -'70's when I started dirt track racing the engines had to be stock. But that didn't mean you couldn't tune for maximum performance. Open air cleaner, no choke plate, some carb work, drill the jets, cut the head .060", made shims for the stock cam pulley to get the cam timing right, (CRITICAL STEP) good valve springs, turned it 7000 RPM. Had to have a muffler so I took the guts out of a glass pack and used the shell (lol) with 21/4" pipe, thing sounded like a pissed-off bumble bee!