Holley EFI harness adjustment

My suggestion is to get the flying lead harness then figure out what terminals you’ll need and reuse the existing connectors. Holley should provide a list of the terminals they use but I have yet to find that anywhere.

You said you have the depinning tools but do you have crimpers? Some Metripack have seals.

Also, I try not to splice wires if I can avoid it.

If you find the need for more than one or two relays use the MSD solid state relay. I use one, makes things somewhat easier.