Check out this recent thread in drivetrain upgrades. In my last post in there I cover how to verify the cam/crank alignment.
http://forums.luvtruck.com/viewtopic.php?t=9702
To be honest though, your description of the symptoms sounds like the truck I have that is 180 degrees out. Shot flames out the carb and backfired like a cannon out the pipe. I just swapped wires on the distributor though. If you find the cam does not match the disti (Should be: rotor at #4 on disti, cam mark&dowel straight up, crank at 0 degrees, 180 out has disti pointing to #1) the easy quick solution is to swap the plug wires. Switch 1 for 4 and 3 for 2, should fire right up if all you are is 180 degrees out of time.