What kinda wiring and relay for fuel pump?

You need to post what Holley says about this specific pump, IE wire size recommendation and amperage draw.

Also, "it's complicated." If you have the old style ammeter, and you tap something right off the battery, the ammeter will not show accurately, but on the other hand, if you tap off the correct side of the ammeter, this puts EVEN MORE load on the already inadequate ammeter and bulkhead wiring.

One place to tap off is right at the big nut on the starter relay, this is "same as battery", and once again, this will make your ammeter readings "funny."

From that tap, run a fuse (depends on the Holley pump draw) to a relay--which also depends on pump draw, and use the ign run (blue wire) which feeds coil, regulator, etc, to "fire" the relay. If you want an additional toggle, wire that in series with the coil to the "blue" wire. I would guess you want at least no10 wire back to the pump, but ONCE AGAIN this depends on how large the pump is and the amperage draw.