Again: Unleaded or leaded fuel for mid 70's /6?

Rat Bastid said
Im going to test some either tonight or tomorrow. It largely depends on how motivated (or not) I am.

Since you most likely have the thingamjig up and running, I’m motivated to finely pull my mill out. Drink a few ginger ales, run some power pulls and test some fuel on it before we finely put those heads you ported on…