orange box failure

You changed the ECU and then got spark, thus you conclude ??? When you have time try putting the orange box back in. Simply removing the old (possibly rusty) sheet metal screw may have given you back the required ground connection.

Any HEI type kit will simplify your wiring and improve reliability (no ballast, etc). You can leave the old wiring and stuff in there for that "period look" and wait for an under-bay cleanup to strip the old stuff out. I got HEI parts from 80's GM trucks for <$20, just snip and go.