Is a rotating assembly kit for a SBC the same as a LT1 except the 2 piece rear main seal vs the 1 piece rear main seal crank?

 

Depends on the year of the SBC. I believe that sometime around 1987 GM changed all SBC blocks to one piece rear main seals, at the same time they went to roller cams. Later model SBC rotating assemblies will fit the LT1, but the balance will be off if the crank came from a 350 engine, because the LT1 uses lighter pistons. The crank form a 305 will balance better with the LT1 pistons.

 

Isnt there a difference with the way the crank is balanced as well. aren't most internally balanced and the lt1 is externally balanced? so wouldn't you need different crank pulley/balancer and flywheel/flexplate?

 

I guess tihs is what my question boils down to, I have called CNC Performance about this rotating kit, CNC-Motorsports.com is your resource for High Quality, Hi-Performance auto parts from industry names you trust. Competition Rotating Assembly Kit, 3.480 Callies Crank, 6.0 Compstar Rods, Mahle 10.6:1 Pistons, Chevy 350, and have asked if i could get a one piece rear main seal crank, and they said yes they could switch it.