[drolston]

Long shot. If the rebuild included cam bearings, it is possible that the rear cam bearing went in a little too far and blocked the fuel pump push rod from engaging the cam. Easy check: crank the engine with the fuel pump removed and see if the push rod moves up an down about 0.2".

If the bearing is blocking only a little of the pushrod hole, you can grind down the diameter of the push rod at the cam end enough to pass by the bearing. Easier than pulling the engine to bump the cam bearing into position.