distributor cap male terminal

Use a stock Mopar elec dist [ it is shorter ] & use it to trigger a GM HEI 4 pin module.

That is what is inside the MSD R to R dist, a GM 4 pin module on a printed cct board.

The Mopar reluctor fine tips will also give you more accurate cyl to cyl firing than the thick, large gap, rel junk that MSD uses.