383 L98 (400 SBC crank). It has to have the one piece rear main. And is it still externally balanced? I want to use a 6 speed tranny and the LT1 twin disk setup, but if its still externally balanced, I cant use the LT1 flywheel. Or can I? TIA. Im tryin to get everything straight before I jump in.

 

Centerforce makes two flywheels for the T-56. One is for internally balanced 350's and the other is for externally balanced 400's. Several aftermaket companies make a internally balanced 383 crank that you can use the stock LT1 flywheel with. The only real problem is with the new 383 crate motor from GM. It is externally balanced AND one piece rear main. No T-56 flywheel for it yet.

------------------
1992 Pontiac Firebird 350/Six Speed
1987 Toyota Pickup 383/500+ HP

 

I have a 383 MR in the works w/T56, the block is at the machine shop right now.I'm using the cast SCAT one piece rear main seal, it's good for up to 600 hp N/A and I'm installing 4 bolt main splayed caps.I have a McLeod street twin clutch (LT1) that I will be using, everything is going to be internally balance by the shop.

------------------
1987 IROC w/T56 and a 383 TPI in the works