3/16" cross section on the upper O-ring sounds a lot too large to me. At least I've never seen one that big. I'd be worried about reducing the mesh contact between the distributor pinion and the camshaft drive worm with such a large upper O-ring. Are you sure the old one you were using as your baseline model was actually an OE item, and not oil-swollen? I'm not!

(Remember, they've always sold Chrysler Blue paint in rattle cans...and engines were painted on the assembly line before distributor installation.)

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Dan,

This fat o-ring fits into the block recess just fine. It doesn't look like the o-ring was painted, but that a little blue rubbed off on the periphery. The o-ring is hard, but not brittle like the small one. If the new o-ring doesn't fit well in the block I won't use it.

How did you determine the replacement o-ring dimensions?

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Joshua

Got the O.D. of each out of the FPC, but don't remember how I determined the cross-sectional area. My recollection could be skewed (I don't have one of the O-rings in front of me); if 3/16" fits...

...it fits!

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一期一会
Too many people who were born on third base actually believe they've hit a triple.