My Slant 6 and the re-do

I am pretty sure that your engine is a later year than the cable-shift transmission (since 5 core plugs in a row). You can check the block casting#. If your car has an early transmission, you will need a $20 spacer ring on the torque converter to snugly fit the crankshaft hole. Otherwise, the assembly will be imbalanced. Check that the prior owner did that.