383/6 speed questions?

last year i built a 383 for my iroc and now am going to put a 6 speed in it.Will i have to balance the flywheel and will the flywheel off of an LT1 bolt on.

i had to balance the flexplate last year when i built the 383

If it's a late-model (1-piece RMS) engine then the LT1 flywheel will bolt up. If it's a 2-piece block you'll need a conversion flywheel.

Since you had to balance the flexplate, you must have an external-balance crank which means you'll need to balance the flywheel too. You can just take the flexplate off and carry them both to a machine shop and have the flywheel balanced to match the flexplate.