HEI in Mopar ECU casing
I work in aviation, almost a whole aircraft is made from aluminum. Fuselage, wings, tail, etc. Electrical system is same concept positive thru the wiring, negative ground return to the batteries thru the airframe. Metal is metal as far as electrical grounding is concerned as long as its clean to be able to conduct properly. HEI stock distributors are aluminum, and modules are bolted directly to them, wont be any different. You must be thinking about magnetism. You can always sell the chrome box and coil if you dont use them. Or return them if the seller allows returns. Theres guys on here that blaspheme over GM HEI conversions only because they have tunnel vision to anything but mopar. Maybe you can sell those parts to them.