Replace the pickup coil. How bout the coil. This is HEI, right? What capacitor we talking about?
If the header tubes are hot, it has been firing the plugs for sure. If it's spraying gas out of the primaries, it seems to me it's a valve timing issue, or at least maybe a possibility the valves are too tight and not closing right.
Try my valve adjustment procedure. Worth a shot. If the valves are too tight, it won't start. Same with being too loose.
http://www.73-87.com/garage/valvlash.htm
If you don't want to buy timing tape, you can use some masking tape and lay it off at four 90 degree increments. Or you can just lay the balancer off just as easy.
One thing about it, when you finally do figure out what it is, it will be something simple. It always is.