Big block, auto trans, mini starter with headers and console shifter.

So a couple months ago I was leaving a local show and got a *click* when I went to start it. Tried to jump across the starter relay terminals--nothing but some sparks. Hooked up the jumper cables thinking battery was dead--nothing. Then I saw the wire from the starter relay to the starter was a little burnt by a header pipe--aha! So I jumped across the terminals at the starter and she cranked right up.

When I got home, I replaced the wire from the relay to the starter. While I was at it, I replaced the relay and positive battery cable too. Fixed!!! Or so I thought.

Yesterday it started doing the same thing again! So is it the contacts in my starter? Not much left to replace. What's a good source for the contacts.

(I'm still not sure why it will jump across at the starter but not at the relay??)