Jon, that sort of reinforces my idea that there are two types of Pertronix units- - - -the ones that have failed, and the ones that will fail soon. Another problem I've observed is that the "snug-fitting" trigger usually has at least one degree of rotation slop on the distributor cam, and sometimes as much as two degrees. Every degree of inaccuracy at the distributor shaft creates two degrees of random timing error at the crankshaft. Bad juju!
Jerry