I think it's simply a timing issue. The EA's are very sensitive to changes in timing from the dizzy. Twice now after doing some work on the engine, the car wouldn't start and both times it turned out to be ignition timing. It could be that, but if your getting backfiring through the intake that means your timing is severly advanced.
Another thing, you say it's not 180 degree's out because the piston is at the top of the cylinder. The piston goes up and down twice for every 1 turn of the cam and dizzy rotor. When people say you are 180 degree's out they mean compared to the camshaft. Pop your rocker cover off, and check that the mark on the cam gear is facing almost inline with the right hand side side of the head. Then set your dizzy so that the dizzy rotor is about 1cm further clockwise then the number 1 mark on the dizzy.
One last thing, make sure the dizzy is fully engaged with the oil pump sprocket which is underneith it. If it's not, you will be able to feel a little gap between the bottom of the dizzy and the block.
I'd be checking all those things, that will eliminate most of your backfiring issues assuming your wiring is all right. After doing all these things, you may find that the car won't backfire through the intake but still won't start. If thats the case that means your timing is now only slightly out and you will need to turn the dizzy a little bit in both directions until you find the right spot.