got the MSD nearly hooked up and ive hit a snag. the digital 6 has a green and purple wire that goes to the dist. my mallory comp 9 has a green,red, and black. i know the green/purple wire hooks to the red/green, but what do i do with the black? the instructions kind of indicates the black wire gets split and hooked to both wires. is this right? thanks Dave

The black wire should be a ground for both units. attach both to a ground source.