What does a stock flywheel weigh, and what's the advantage of a lighter one? On the round tracks, we used a small diameter clutch with three friction discs called a "circle master", I believe, along with a flex plate for an automatic transmission so the starter had something to drive. That one had very low inertia which allowed a driver to accelerate off a turn quicker, and drive deeper into turns- - - -effectively "stretching the straightaway" by a few feet. That clutch was totally unsuitable for street use. Slipping those small discs to get started caused massive shudder- - - -"Rev it up and sidestep the clutch pedal!" I've been known to set up a stock flywheel on a brake drum/disc lathe and whittle about 5 pounds off the back side.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!