Lets go though a couple checks... 1) DOES THE PROP GO THROUGH 360 DEGREES OF ROTATION?
If it does then maybe you didnt have sudden stoppage but perhaps a failure in the ignition circuit - did you try #2 coil ? You could have trash on your #1 points... 2) If the prop does go through all 360 degrees - you can remove one bearing cap at a time and check bearing wear on the rods - just for kicks. 3) If the prop does not turn all the way though 360 but most of the way then I suspect a valve. 4) In the ignition circuit check your rotor that it is still good - Ive seen some bad one on cars before... 5) Remember the three things required for ignition - air-fuel-spark - perform elimination tests from simple to more complex - done tear the engine apart because of a bad coil wire (for example) 6) Fuel filter/lines for trash....? 7-10) You know enough to do some general checks so why am I here? Hope you figure it out....Call me if need be 229-506-7741. Bill and 41768