From post #12:

<< Only thing I did was to reset the points to 0.018" (4.5mm). >>

0.018" = 0.45mm.
If you really set the points gap to 4.5mm, there is the problem.

Harry - that was a typo. I set the gap to 0.018" (.45 mm). Over 6000 miles of driving the points had gradually closed.

Frank - if indeed the chain jumped a tooth, how do you correct that? (what do you change - move the chain, move a sprocket, slightly rotate the distributor, etc.?)

Thanks.
Tom

Nutmeg:

Moving the intermediate sprocket back to the original position would be the preferred fix. That would entail slacking off or removing the tensioner, reaching into the timing cavity (with the cam cover off) with long screwdrivers, pushing the chain off the sprocket, and poking the sprocket around in the direction of retard. As there are more teeth on the intermediate sprocket than on the distributor gear, a one tooth adjustment on the sprocket is a finer adjustment than one tooth on the distributor.