I'm trying to fully seat a freshly rebuilt 57 distributor into 57 y-block 292 engine block all stock.  It's been in before prior to rebuild.  Can't get it to seat the final 1/8", pretty sure it's not engaging onto 1/4" hex oil pump shaft.  Can't figure out a way to stop oil pump shaft from sagging down and preventing distributor shaft from catching.  I already turned crankshaft both ways while pushing down on rotor shaft.  I wonder if a swab of grease will hold oil shaft in place.  Any ideas, other than dropping oil pan?