Flyweel info

[eric8]

So i've got a '77 C10 that's bone stock with the original 350 engine and 3 speed manual transmission. It's my understanding these applications came factory with a 168t, neutral balance (internal) flywheel. Looking at crate engines, some require an internally balanced flywheel and some that are external. Just want to verify, but if I get a crate engine that uses the new 1 piece rear main block, I'll still need to ditch my original flywheel, even if the new crate engine is internally balanced, correct?

I'm also trying to figure out, is a clutch specific to an engine? For instance, will an 11" clutch for a 350 sbc fit any manual transmission or vehicle that has a sbc? Or is the clutch specific to the transmission/vehicle?

[geezer#99]

Yupper!
One piece and two piece flywheels are different. Bolt pattern size is about 5/8 inch different.
Motor doesn’t care what clutch is used just as long as it bolts to the flywheel, fit’s inside the bellhousing and the spline count on the trans matches the disc splines. Some trans have 10 splines, some have 26.

[v30crewcab]

one piece and two piece mains have a different bolt pattern for the flywheel.

[eric8]

Thanks guys!