I'm looking for a post that comes on the rx8 or something similar, a solder on post for electrical connections thanks in advance guys!

As far as I know the post will need to be replaced by sending it in for service. Other option might be to salvage on off a trashed ESC. But that might still be rough to replace, not sure how it is attached.

It's not for my esc I'm making my own cap bank on perfboard and would like to be able to make something simalair to the castle cap bank

Check Radio shack.

I cut the "birdcage " off of my cheap battery connectors then dremel it down to fit the hole in the circuit board.