I have a stack of Mopar flywheels & I don't how to distinguish between a flywheel for an internally balanced engine versus an externally balanced engine. I believe flywheels for internally balanced engines are the same between big block & small block of the same diameter but are different on externally balanced engines of the same diameter. So how can I tell which flywheel is for which application? Thanks! GTS

The basic 130-tooth flywheel didn't change from '62 until the end of production, even the same casting number and they were used on both BB and SB.

External balancing was usually done by drilling a hole or holes of a certain diameter and depth; some external balance drilling is easy to spot but some, like the 340, is so small it can be confused with mass balancing drilling. In that case it helps to know the location of the external balance drilling in reference to the crankshaft bolt hole positions.

Best to post pics of the flywheels in question.

Here are the pics. All flywheels are indexed with the 2 closest crank holes at the top.

#5 and #12 look like the cast crank versions with the large shallow drillings. The rest look like 'zero' balance pieces.

#5 and 12 are definitely external balance, diameter and depth of the three large shallow-drilled holes determines which engine.

Even #8 with the fly cut & #9 with the 3 extra holes are for internally balanced engines? Thanks! GTS

Keep in mind that cast iron is not as homogenous as a piece of billet and the fly cuts are likely for zero balance.

Is 21 a mopar flywheel ?

What do the front sides look like? If they have been cut at least once past the factory cut and/or are heat checked, and hard spotted, they might be scrap?

I had an old Ansen that was back-cut like that wheel with dual paterns

Gus

#21-Early /6 trucks 11" 172T ring gear for direct drive starter
#17/#2 70-2 440 heavy rod (6pk+HP) 10.5"
#12/#5 360 truck 11"
The rest appear to be neutral balance.

Reason I asked is because the bolt pattern is not the same as the others.

Dan B to the rescue.

Thanks all, especially Dan! I was pretty sure one of the flywheels was from my 70 GTX. GTS

#21 does not have the Mopar bolt pattern, I don't know where I got it! GTS

I have a 4 speed project coming up & I have a cast crank 440 that I want to use. What does the correct flywheel look like for this application? So I know what to look for? Thanks, GTS

All cast crank BB's use the same external balance.

That's what I needed! Thank you!