American Motors: AMC 304 running rough and backfiring, spark plug wires, vacuum leak

Question
My Jeep 304 just cut out on me one day. Replaced all ignition components and carb. I found a broken wire at the ignition module. Fixed that and now it starts but runs rough and backfires out of the passenger side exhaust. I put the #1 sparkplug up on compression and the rotor is pointing to #1 sparkplug wire. Also, the timing mark on balancer is pointing to TDC.

Now, when idling and puting a timing light on the balancer, the Jeep will run very rough on TDC and I have to turn the dist. way advance to where I can't even see the timing mark to get it to run somewhat desent. Still has mild backfiring out of passenger side exhaust and runs weak.

Timing chain jumped timing? Or is it valves in the passenger head?

Thanks!!!
Tommy

Answer
Some things that can cause backfiring is a broken valve spring or rocker arm bridge support; spark plug wires crossed; distributor cap; vacuum leak at intake manifold; or burnt valve(s).
I would pull the valve cover and check for a broken bridge support.