this is an 87 pickup with dual tanks , I'm helping putting a 400 sb in for friend and he wants to use a 750 edelbrock .fine I say. all in and runs fine. Problem fuel gauge is pegged all the time he used a mechanical pump and older non efi pickups in the tank. There are 2 wires that go to each pump (old efi units) so how the heck do we make the gauge in the dash work correctly ?? Does he need a whole 86 harness or what ?? It still has a selector valve also Thanks !