That big belch could have caused it to jump timing. But you would
usually sense the engine turning over much quicker. What does that mean
when you say "It seems to be firing OK"? If it were firing OK it would
be running. If it's flooding maybe you only have a choke problem, which
could have contributed to the belch. Hold that choke wide open with a
screwdriver or have someone assist you in doing so.  Holding the gas
pedal to the flood as you start should unload the choke as well. If
this works than you could have a bad choke pull-off, which was very
common. That's a small vacuum valve the pulls the choke open when the
engine starts. Usually the diaphram leaks and fails to hold vacuum.
Epoxy around the crimp edge of the valve will fix the leak unless the
diaphram is ruptured.

Timing Chain ? It could turn over forever and never start. Same thing
if it was the coil. I believe a 1981 has a coil.