Need to be ready to check it when the problem occurs.
Spark: Check the spark at the plugs, work your way back to the coil. Check the power to the coil, check the points and point gap, check the distributor shaft bushings.
Fuel: Have a wrench ready and pull the carb drain plug when it quits. If there is little or no fuel flow, the carb isn't getting gas. Could be a restricted sediment bowl screen, clogged fuel inlet at the carb, sticking float or needle valve, gas cap not vented, fuel line too close to the exhaust causing vaporlock.
Compression: Not likely, but tight valve lash can cause low compression when the engine comes up to temperature.