International 340 backfired and died

Two types of timing, ignition timing and valve timing. Both are direct causes of Backfire problems.

If ignition problem (simple) the points self destructed, ot the rotor/cap got water in them and is crossfiring (why did chrysler name a car for bad ignition). Or the cap got bashed by a branch and moved far enough to break the rotor drive spline on the dist shaft.
If ignition problem (complex) the drive gearing to the distributor has come to grief. somewhere between the hyd pump, and the breaker cam. There are usually gears and bearings, and centrifugal advance springs and stuff in there that might be broken.
The Ignition timing is also directly controlled by the valve timing gears from the crank to the hyd pump drive. If this system goes out, or slips it is either bad , or very bad.
If bad it is just a keywak or drive hub or pump shaft drive giving wrong rotational relationships to thje dist. If it is very bad, it is the valve timing mechanism and that requires removing the fromt cover and getting much dirtier.
Good luck and I hope it is a broken rotor.
JimN