I just put an HEI in mine also and have a wiring question. There is the original coil wire with a spade connector that shows 12v KO, and then there is a black wire with a yellow tracer that shows 12v key on. The blk/ylw wire has a connector that will plug right up to the HEI + terminal and isn't used, will it work? I have no clue what it was originaly used for but the car now has a BBC.

BTW, My HEI just required a little clearancing of the firewall to fit. prob just a 1/4". Used a propane torch to heat the firewall a little making the metal more maleable and gave it a couple love taps.