Pearl;

I suspect you MAY have gotten the bolt, washers, and insulators either not quite in the right order on reassembly...or maybe even just off center, or the insulating qualities of the ages old fibre washer or insulation piece inside the dist housing may just not be up to the task.

Start by inspecting the place where you see the spark and ascertain if it is a spacing issue or installation problem or material failure. The OE fibre washers have steps, which should be installe toward the dist housing to keep the bolt centered in the pass-through hole (but to assure this, I like to add a plastic sleeve to the bolt). It's simple, but easy to introduce a problem, and has to be right, or the ignition. Check it out...that spark is telling you where to start!

If worse come to worse, I'll give you a "stacking order" for that bolt...it is somewhat important if not critical!

Sparks!