>Jarrid -Obviously a lightened flywheel gives you much better performance
>are there any disadvantages of doing this?
Yeah, the engine is somewhat rougher running, and generally requires that the engine be prevented from vibrating too much.
The lighter flywheel gives you less inertia to use when you are letting out the clutch. This makes clutch takeup a little more precise an opperation.
If you miss a shift, the faster revving engine will hit the redline somewhat faster than usual, hastening the distruction process.
For the SII factory competition kit, the rootes people took an exhaust hanger, and bolted it between a bracket on the head, and the firewall. This kept the fuel level smooth in the carbs, which keeps the jets and emulsion working.
Over lightened or improperly lightened flywheels are very dangerous.
Jarrid