Small block timing

Since the engine is pretty much stock the factory timing recomendation should be about right (should be on a label under the hood). Assuming the harmonic balancer has not failed and slipped there will be a groove in the OD of the balancer and there will be timing marks cast into the timing cover on the drivers side of the engine. Line up the zero mark on the cover with the groove in the balancer for TDC. Remember these marks will line up twice on a 4 stroke cycle, on the compression and exahust strokes. To be on the TDC on the compression stroke put your finger over the #1 spark plug hole (Front drivers side of engine) as you trun the engine over and when you feel air pushing past your finger that will be the compression stroke.

You can try advancing the initial timing some to see if you improve throttle response and replacing the advance springs inside the distributor with lighter ones will generally improve performance.