Also, if there is any of the diesel harness left you should be using a PMGR starter on the 460 since the diesels are are already wired for one.
You will want to connect the NSS of the C6 into the starter trigger circuit. (manuals are jumpered under the dash)
I see it would be simple to repurpose the glow plug relay to power an HEI.
It's challenging for me to trace this all out on my phone, and a lot will depend on what's left of the diesel harnesses.
Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.