Stock flywheel? There are probably differences between flywheels as to both weight and diameter (truck and industrial may be 1" larger), the 230 may be lighter than the 218. It's not the scale weight that matters most, it's how much weight is at the rim. I've heard of removing the starter ring gear completely or just grind off the teeth (definitely helps) if push start is OK, but it may be illegal as "part of the flywheel". If DQ, your objection is that it's a separately serviceable part.
Take some weight off the clutch disc and pressure plate, especially close to the rim.
If the race is run without many gear changes, use the smallest diameter clutch an pressure plate that fits the flywheel and increase the spring tension.
Clutch fan with shroud, seal the radiator support so all air must pass through the fins.
