All good items to check below. Just a thought since you do not know what or how bad, I would START with the following. Turn engine by hand and check for spark.
1. Use a breaker bar to turn the engine over. If a sheared pin or no
oil drive etc... do not crank it over with starter yet.
2. Bar the engine in proper rotation till timing mark gets within about 40 50 degrees before TDC. stop turning engine over here until....
3. Remove spark plug wires at the plugs, bring wire #1 and #6 up to a place were you can see both ends at the same time. Place 1 & 6 wire ends on metal so they will throw a visible spark as you rotate engine past timing mark.
4. With the KEY in the ON position and all other wires removed (so it can't try to fire) rotate engine with breaker bar while watching for a spark out of either wire. Rotate engine as much as 30 degrees past TDC if spark is not seen earlier.
5. Stop rotating engine as soon as spark is seen or until about 30 degrees past timing mark of TDC Turn key to off position
Timing mark on damper can be showing #1 cyl. or be 180 degrees out that is why I had 1 and 6 plug wires at same place looking for spark. If a broken drive pin you will not get a spark. If ignition failed no spark. If timing chain jumped a tooth you probably can not turn engine with a breaker bar as valves will contact piston. By baring the engine and not cranking with starter you will not hurt anything and not spinning crank with no
oil being supplied. If no spark you have a direction to look and can remove Stack to get to the distrib to look farther. Good luck