Regarding the info in the "green book" -- when installing the cam and gears the marks align with the #4 cylinder in TDC-firing position--it is confusing. Don't take your pan off. Remove your valve cover, turn the motor by the pulley bolt until the timing mark on the pulley and timing gear cover align and you have clearance at both the intake and exhaust rockers on #1 cylinder. If they are tight and the rockers for #4 have clearance, rotate the motor another full turn. Now you can withdraw the distributor drive gear and set it in place as the book shows, so the distibutor rotor will point forward and a little towards the block when looking at the motor from the front. You can rotate the oil pump shaft easily with a long screwdriver--it only has to be close. With a wrench on the front pulley bolt rock the engine back and forth while pushing the distributor drive gear down to seat it into the oil pump. The distributor should fall into place with the hash mark on the top edge for #1 in the forward/slightly towards the block position. That position will allow for the vacuum retard/advance to have clearance.