Yet another truck off the road.. Any help?

[Bradydz]

Driving home today, going a steady speed, my truck randomly made a loud bang/pop (I don't think it was a backfire, it sounded like the sound came from in front of me, whereas when it backfires, I can hear it behind me). After that, my truck started lurching and trying to die. When I rev the engine, it doesn't seem to have any problems, but once I actually start putting a load on it, it tries to die, and lurches, and did actually die a few times. Any ideas on what to look for? I have Pertronixs, so no points. And I checked my fuel filter, it is getting fuel the whole time. New spark plugs, only a month or so old.
Possibly timing?
Engine is a 355 (327 with 350 crank, bored .30 over)