I was going to suggest unhooking the vacuum advance in case the internal wires are bad, like all ready has been suggested. Its a quick test, just remember to plug the vacuum line. How about the power lead up to the HEI, or the key switch?
My buddy chased a miss in his dirt track car for almost a whole season, turned out to be the $1.99 lighted toggle switch they had for ignition switch!
Joe
