O.K. Andrew,
the sacks 153 runs good stock but if you increase the transfer and exhaust timing, lower the intake down a little and daul port the muffler it will suprise you with the power output. thats stage 1, stage 2, advance the ignition 8 to 10 degrees, more compression by milling the base so you have .030 squish clearance and enlarge the carb venturi . stage 3, cut off the cylinder head and build a new cylinder head with a smaller combustion chamber and install a expansion chamber, install a ht-1 carb off a 084, buy a racing chain and you'll be able to go racing. probably run agains't Homedelight man
ken kdhotsaw