366 Big Block Flywheel Question?

I have a 1977 Chevy Suburban with a 400 engine and automatic trans, I want to replace the 400 with a 1985 366 big block...my questions is will a 1972 402 flywheel for automatic trans work for this replacement? If not what model/engine flywheel can be used? Thank You In Advance. :)

The 366 is a GMC engine, usually found in bigger trucks. But came with automatics (Allisons in many cases). They are native to school buses, 50-70 series trucks. It has something like a 3.937 bore and a 3.75 stroke.

Outwardly the 366 looks like any Chevy big block and will swap in place for up to a 502 truck motor, so it should be a go in your case. The 402 block is same family so the flex plate should fit.

I've swapped around truck standard transmission parts between big and small block Chevys and it has always worked for me. I used to prefer the bigger clutch and cast iron bellhousing for Chevelles and BelAirs.

Bob