ok I have a choice between a 15 lb vette flywheel or a aftermarket billet 30 lb flywheel. Running a 305 with a super t-10 with 3:50 gears. I know the 15 lb will rev quicker do to less rotational weight but will it have enuf inertia? thanks, Bob

 

The lighter flywheel will of course rev quicker, but it will also cause the rpm's to drop quicker as well when you lay off the accelerator. If you have to drive in hilly or mountainous roads, the engine will constantly have to be highly revved just to keep the same speed as the heavier flywheel.
I imagine there should be a large difference since the lighter one weighs half as much as the other.