Oil pump/crankshaft gear alignment tool is used to align the oil pump gear flats with the flats of the crankshaft in Twin Cam and Milwaukee Eight. We recommends assembling the camplate, oil pump, camshaft, etc together on the bench, lining up oil pump gear flats with crankshaft flats and installing the complete assembly into the camchest as one complete unit. This procedure has proven to provide the best seal on the back scavenge port of the oil pump to engine case as the parts are always going inwards towards the scavenge port. On Twin Cam engines rotate the crankshaft flats so they are horizontal and align oil pump gear flats horizontal to match. On Milwaukee Eight engines rotate the crankshaft flats so they are vertical and align oil pump gear flats vertical to match.