Question regarding changing my shore power hookup???

You want a 50 amp 4-wire shore power inlet. The 4-wire is important, as there's also a 50 amp 3-wire, which is one less wire than you'll need. (Safety Ground, Neutral, L1 and L2)

Here's a few options for inlets:

Marinco 50 amp

And the mating female plug:

Marinco plugs