1942-62 only on flywheels for correct fit. 1938-41 have the same bolt pattern but use 3/8" bolts to attach to the crank instead of 7/16" and the pilot hole in the center is also larger.
In a pinch the 3/8" bolt holes can be drilled out, the center pilot may not be that big a deal as the three line-up pins keep the flywheel in position. I have seen it done.


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