Backfiring out exhaust

So I decided to check the timing on my 440 in a 69 barracuda. I could not retard it enough because of vacuum pod so moved the oil gear to get more adjustment on distributer. Now can't get it to run without backfiring out of the exhaust. I pulled the #1plug and bumped it until ait blew out. Then made sure rotor was pointing to #1 wire.then double checked firing order and it is still backfiring. Not constantly but sporadically.i checked the coil and it is 1.7 and 10000. I'm at a loss. Any suggestions?