Anyone use this distributor cap?

The vented caps are good. Vents the Ozone gas that builds up from the arcing of the rotor tip to the cap terminal.
There is a lot of high and low voltage zapping going on in a dual point at 6000 RPM ...lol

Closer tolerances between the rotor tip and cap terminal reduce the length of the arc, so filing the gap to fit can be a good thing.

In this case ... it looks like you need the correct Firecore rotor because it looks like the cap terminals are moved way in.


Ionized Gases
Gases may in various ways be put into a state in which they conduct electricity on an altogether different scale from the normal ambient atmospheric gas. They acquire this conductivity when gases are recently driven from or near arcs.