[DougD]

Ikestaa
Definitely do a search on this topic. I asked similar questions a few months ago. As I recall, MSD has several different caps that fit their FE distributor. One needs to procure the smallest cap. Of course you'll need an MSD dist...

On your Motorcraft dist., try turning the distributor body a few degrees one way or the other and see if that makes some room. Rearrange the plug wires to maintain proper firing order and timing.

If you can find a junkyard puke tank, you can salvage the mounting plate that attaches to the intake manifold for a spacer. Should provide about 3/4" extra room.