Install/Wiring Mini Starter

I bought a mini starter a while back and would like to finally install it.

Whats the easiest way to remove to old starter. I have a 68 Dart 340 with Headers, and it looks like a pain!

Next question is what wires do I run to the mini starter? I remember checking it out last year and it would engage but not spin, I'm hoping I did something wrong.

Thanks as always!