I want to use the stock flywheel off my '87 LB9 on my current 350 (gmpp vortec headed engine). I just had it turned today but figure I had better make sure, the balancing crap is confusing to me . . .

thanks

 

if the old flywheel is for a 1 piece seal and the new engine is it'll work. you can't interchange parts between 1 piece and 2 piece seal engines.

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-=ICON MOTORSPORTS=-

 

cool, thanks . . . the more I looked at aftermarket units, the more I grew concerned about internally/externally balanced engines and flywheels. I'm going one piece rear main to one piece rear main though . . .

 

As said you can't use them inbetween engines. Here are the reasons why:

Two piece rear main SBC's use a neutral balance flywheel, except for the sb 400 because there isn't enough room for counterweights on the crankshaft. Two piece rear main seal flywheels also use a 3.58" crankshaft. These were used until 1986/1987 depeneding on car model

One piece rear main SBC's use a counter-balanced flywheel and have a 3" crankshaft.

These rules also apply for chevy V6 engines.

Flywheels and flexplates come in both 14" (168 tooth) and 12 3/4" (153 tooth) sizes. You can fit both flexplate sizes into a 700-R4 which will give you more mechanical advantage thus giving you more torque. However, you can't fit a 14" flywheel into a T-5 bellhousing without bellhousing modification which in any instance (high stress) where you'd use a 14" flywheel the structual stability of the bellhousing would be comprimised. It would be better to use a lakewood or similiar SFI approved bellhousing for these applications. Two piece rear main seals, albeit more leaky, are recommended for heavy duty applications.

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1984 WS6 Trans Am Hartop
Former L69 Car under restoration
1984 WS6 Trans Am T-top car
4-bolt main 350, headers, Holley 650, T-5 and 3.23's.
Daily driver and restoration