HEI also has problems with the green and yellow wires going from module to the center coil of wire inside the distributor. These wires move every time the vacuum advances moves and over time they can break.
Another area to look is at the coil contact to rotor. There is a tiny spring touching the coil bottom and a brush like material touching the rotor. If either get dirty you can get problems. While checking the coil, be sure the ground terminal is installed and screwed to the coil.
A friend of mine chased a high rpm miss in a dirt car for a year and a half, turned out to be the $1.99 lighted switch they used for the ignition!
Joe
