Timing gears rarely jump, no chain in that engine. If the gears jump, you have a major problem.
Like the guys above said, pull the valve cover and rotate the engine watching the #1 valves or pull the #1 plug and hold your finger over the hole till you feel compression. Once compression comes up, watch the for the timing marks to align. This is where the rotor and #1 wire should be aligning.
Keep rotating the engine till the timing marks are in in alignment. Ground out number #1 spark plug with the wire attached. Loosen the distributor hold down enough to rotate the housing with out pulling it out.
Turn the ignition on but don't rotate the engine. With ignition on, twist the distributor housing back and forth watching for spark at the plug you have grounded. Keep twisting till you narrow in on the spark, you should be able to get really close to right on the mark.
Lock the distributor back down, install the plug, and see if it will start. Timing should be with a degree or two.
Joe
