.....like this.....can you use the MOPAR three prong one from the mid 80's instead of the GM one......I'm at least hoping that the MOPAR plug will fit the GM switch.

Which "switch" are you talking about - or do you mean the "relay" ??

The oil pressure switch, which shuts off the fuel pump if there is no oil pressure, unless in start.

Correct

AKA a Hobbs switch. I used a similar system on my old bracket car and it worked well. I only had one of the old Holley 110 GPH pumps and did not use a relay then. My new racer uses the Holley Black pump and I will be wiring in the relay this time.

Sweet

Mount the realy as close as possible to the pump. feed the relay with the proper gauge wire for that load Use the trugger wire from the ignition switch to activate the relay, not to feed the fuel pump You may need to put a push to bypass, open, the ground wire from the Hobbs switch to allow the motor to start and build oil pressure before the Hobbs switch operates correctly IHTHs

I really would like the relay under the hood, could I run a bigger wire from the relay to the pump?

I would rather not have the relay under the Ramcharger.....daily driver....I've had an extra blue pump laying around so I'm going to use it on this, but like I said I would rather not have the relay under the truck. All the instructions say to do it, but....man....I would rather not. In my Valiant I put in the trunk.

I went ahead and bought the GM switch....it would be nice to use the three prong switch that the mid 80's Dodge truck used, but that's the berries. I'm going to use that mopar plug for the GM switch.....thanks for everybody's feed back.

Yes, you can mount the relay under the hood and run a large gauge wire to the pump, but then what is the point of using a relay?

The relay is in place to allow the use of a light trigger wire to engage the pump and that is assuming that you have mounted the battery close to the pump and only need a short length of heavy wire from the relay to make the connection between the battery, the pump and ground.

If you don't want to mount a relay, then use an electric pump with little amp draw like a cheap low pressure Carter that would not need a pressure regulator.

The point of using a relay is so that hte relay can safely and adequately handle the load and not alight duty switch. You'll note where the OEM's mount their relays? In the engine compartment, yes even the fuel pump relay. I'd rather not have a long, heavy gauge wire running the length of my car that is always hot and that's what you'll have if you mount hte relay by the pump.

Agreed....I'm thinking just cover the power wire coming from the relay really good feeding the relay off the breaker and that breaker being feed from a madd terminal that's feed off the alt.