There is a notch on the crankshaft gear that will line up with a mark on the oil pump at 12 o'clock position. The camshaft gear has an arrow and an "A" that will align with the housing behind it at the 12 o'clock position. To install the distributor, have the crankshaft and camshaft at TDC, align the notch on the bottom of the distributor housing with the dot on the gear- not the roll pin, the dot. Install the distributor and you're set.