This is strange. The engines are using the 8-pin modules like this:
4-pin connector. R & E are connected together with a wire loop. B goes to true ignition. G has a blanking plug, so no connection.
2-pin connector. - & + of coil.
I've never seen the 8-pin wired like this before, and Goggle is no help. I'm going to be working on these engines (boat has two 350 ci) today & Saturday.
Auto parts place recommended the Accel #35362. I can't find any instructions for it. So, anyone have experience using these modules without a computer, that can confirm they should work like this?

UPDATE: Well, I got it to work. The coil has two connector plugs on it. One wire goes to true ignition, other goes to tach on the 2nd plug. I didn't get a chance to see if the Dwell changed, but the timing didn't change at all. No advance, or retard. The customer can now sell the boat with one working engine now.