As they say, if all else fails, read the instructions. But as luck has it, a Eastwood rep just call me back and said that epoxy primer is acceptable base for their chassis black paints. Just have to leave enough dry time for the solvents to flask out of the primer, 2 or 3 days if possible , then scuff and primer. Well, I left about 10 hrs. from the time I applied the primer to the paint time. See what happens in a few days. Will update .
I wanted to use something that was more resistant to under the hood chemicals, fluids. Ed