it really sounds like to me that you have the firing order screwed up
A 302 non h.o will fire up on the H.o. firing order. it will be running on 4 cylinders. I had my 351w wired like a non H.O. and it ran. not well but it did. I think it is a timing issue more then anything. Perhaps remove the spout connector so the computer isn't controling the timing.
i know i did the same thing on my 331 lol (long story)
got it to start but running really ruff shakin and vibratin