360 Swap Flywheel

Tech Question


Dan Kunkel, Black Hawk, SD, 86 dodge w100 318


I’m currently in the process of swapping a 360 from a ’74 dodge truck formy current 318 in my ’86. I’m having trouble finding a flywheel for thatexternally balanced 360. Several places have order a flywheel in for mejust to have the wrong one show up. The last place listed an internallybalanced flywheel for ’78 and later 360’s. What’s the deal? Should I keepsearching for the seemingly mysteriously balanced 360 flywheel or go withthe interanlly balanced one that showed up in their computers?

Thanks a ton! Dan


Dan, all factory 360s are external balance. I can’t explain the vagaries ofthe aftermarket – ask them why they are so screwed up!

But why not just drill the 360 balance holes in the 318 flywheel? This iswhat the factory did! This trick works fine on any and all ferrous-metalflywheels (i.e., steel or iron), and the specifications on the drawing arecorrect for all ’71-92 360s.

The bad news? Expect to pay fairly big bucks for the drill bit. However, youcould also do the math and remove the required mass – 19.79 in.-oz. – byusing a pattern of smaller diameter holes.

So, you’re welcome, although, as you can see, maybe not a ton.


Balance drilling specs for all '71-'92 360s with ferrous metal flywheel.
Balance drilling specs for all ’71-’92 360s with ferrous metal flywheel.

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