RE:AMC 6cyl flywheels

[Guynn <amx69@xxxxxxxxxx>]

Tom,

Let me say I am not 100% sure on the six cylinder engines. I have indeed 
worked on some but I have never treied any flywheel swaps. Let me 
explain V8s as I know them and then what needs to be learned is does the 
same apply to the Six.

On V8s the O.D. of the crank flange is the important point. The flywheel 
registers on the O.D.  The V8 uses 4.5 inch [nearly all]  and it also 
uses 4 5/8. [very, very few] So, you can't swap a 4.5 onto a 4 5/9 O.D. 
at all. You could swap the 4 5/8 I.D. flywheel onto a 4.5, but I imagine 
it would be wobbly.

I do not know if the six cylinders ever changed the rear O.D. of the 
crank flange. Also I want to add, this
4 1/2 or 4 5/8 does not seem to matter if it is Late or Early 
crankshaft. In other words you could have a 17=971 and earlier Flat 
crank with 4.5 O.D. just as well as you could have a 1974 Torqueflite 
crank with a 4.5 O.D. It 4.5 vs. 4 .625 does not seem to break along 
year or engine size. In over 30 years I have only seen one 4 5/8 crank. 
And only sold one flywheel for one. I sell a lot of 4.5 flywheels. In 
all engine sizes and years.

All six cranks use neutral balance so it should not matter which size 
engine it comes from. Check with a few other six owners and measure the 
O.D. of a few cranks and go from there.

Good Luck,

Randy Guynn