451 misfire above 3500 RPM

[Garys1969RR]

Just found out why this 451 in a 1965 Belvedere was missing. Swapped in a dist from my sons 383 and it smoothed out. These are both Mopar stock elec ignition set ups. On close inspection of the wheel and pick up, we found that at some time in the past there must have been contact between the wheel and pick up. This wore down both the wheel and pick up, where there is supposed to be an air gap. Amazingly O Reilly Auto Parts had the wheel available. Should be here tomorrow. Cost of $8! Advance has the pick up available for $20.

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I have seen this problem in a lot of distributors. Not sure how this happens, but maybe the bushings wear out and the sloppy fit then results in contact between the wheel and pick up.

 

[miller]

Hmmm. Never had that prob with a dual point.

Okay...I'll keep my mouth shut.

 

[72Fourspeed]

This must be more common than I'd thought. That is what we found while chasing an ignition breakdown in my 72 400 RR. Definitely sloppy in mine.R&R distributor,problem gone.