What starter solinoid do I need?

[signsup]

Bubba converted to 12v and has starter solinoid mounted on firewall. Negative battery cable feels like it goes behind the battery down to the fram and the positive battery cable goes to the solinoid and comes off the solinoid and goes to the starter.
So has Bubba also converted to negative ground?
I know I need a replacement solinoid as this one just clicks and lightly tapping with larger and larger hammers has not fixed the issue. So I need a replacement. 12v negative ground five post like the current one? Or just three post?
I'll hang up and listen.