AMC 360 Flywheel vs 304 - Whats the diff??

[JOHN360CJ5]

What is the difference between the 304 and 360 flywheels? They both weigh 30lbs and have the same starter gear and bolt pattern.

[dbesade]

What is the difference between the 304 and 360 flywheels? They both weigh 30lbs and have the same starter gear and bolt pattern.

Balancing. You can't use a 304 flywheel/flexplate on a 360 (or vise versa) because the flywheel/flexplate is balanced per CID.

Go get a 360 flywheel/flexplate from the e-store or have the existing one rebalanced for a 360.

-Dave

[tufcj]

If you look at the back of a 360 flywheel, at the outer edge there's a cast in block, about 1" square and as deep as the flywheel, on a 304, it's not there. That little amount of weight and where it sits keeps the 360 from vibrating.

I've seen guys get away with a 304 flywheel on a 360, I've also seen that combo vibrate so badly it cracked the bellhousing. As much work as it takes to change a flywheel, it's hardly worth the experiment if it goes wrong.

Bob
tufcj

[JOHN360CJ5]

Ah Ha ! Thanks for the info ! I built my 360 many years ago and had the whole engine balanced with the 304 flywheel that I had on hand. The 360 that I got used was off an auto trans, so I rebuilt it and used my old flywheel. It has always run smooth.

Is there any benefit to replacing this now, as I replace my worn clutch disc ??

[dbesade]

had the whole engine balanced with the 304 flywheel that I had on hand.

If the flywheel has been balanced on a 360 then you should be good to go.

-Dave