GM 8-pin hei weak spark

With the 8-pin GM HEI module, best and easiest to use the GM e-core coil which goes with it since you just grab the GM cable which connects the two. Magnum engines have a similar-looking e-core coil, but would have to fab your own custom cable, if that interested in staying more-Mopar. Re "why the 8-pin?". Because it is best, using sealed weatherpack connectors and easy coil connection (above). Only other thing needed is 12 VDC to the coil and ground. The white wire from GM coil is for a tach signal (optional). You don't need to use the other module connector, but can for spark control from an engine controller like Holley Commander 950 which offers a special cable for that. Best to run a dedicated ground wire from the HEI module mounting screw, and ditto for the Mopar ECU and Vreg. More grounds is always good.