Flywheel question

[Devildog]

Hey guys, I've got a quick question regarding a flywheel for a 350 crate motor that's in my 70.

The car is an original 4 speed car that the previous owner swapped to an automatic for his wife because it was her car. The pedals are still installed and I have all the shift linkage as well. The trans, flywheel, and bellhousing were sold.

Fortunately I have a newly rebuilt M-20 4 speed that was going to be installed into my old Chevelle but I opted for a Tremec 5 speed instead. So my plan is to swap the car back to a 4 speed.

The car has a newer GM 350 crate motor installed and I found on their website 2 different flywheel numbers. One is for the 10.5" clutch and the other is for the 11" clutch. I haven't had a small block in over 25 years and I'm not sure what flywheel/clutch combo to use? I'm pretty sure that on big blocks the larger flywheel requires a different starter.....as I recall the 468 in my Chevelle needed a starter with offset starter bolts.

How does this apply to a small block car? Any thoughts or advice?

 

[tom3]

Same deal. Large and small flywheel and the start has to match up. Angled bolting for the large flywheel and straight across bolting for the small flywheel and the bell housing for the smaller flywheel won't work with the large. And the flywheel bolting to the crankshaft might be different depending on the year design of the crate motor. A good 10 1/2" clutch is probably fine for a stock motor, most aftermarket flywheels have bolting for either size though. Clutch spline must agree with the transmission input shaft.
Here's a pretty good read for more info:

TECH GUIDE: Choosing a GM Flywheel-What You Need To Know - Modern Driveline

A guide to selecting a GM flywheel like Crankshaft register diameter, tooth count. engine balance etc.

www.moderndriveline.com