Pass the bong please.....
You'll have to cut and grind the stud and nut under the oil pump. Relax though, building a small block Mopar is just that, building. Chebies are assembled.
When I built my motor there was not a single part I bought that didn't need modification to fit and work properly or that required another previously installed part to be modified. I became quite adept at using a Bridgeport, metal lathe, drill press, band saw, die grinder, hacksaw and various files. At least you'll know that when you are done you have really accomplished something. Enjoy.