Fuel Pump Relay

I am putting an electric fuel pump into a '75 ElCamino. (LSx engine). I want to use a fuel pump relay that will sense when the engine quits and shut off the pump. I know that many vehicles had this type of relay (I presume that newer vehicles do not use this type of relay, but are controlled by the computer instead).

I'll probably get something out of a wrecking yard - I would like to get a relay AND socket.

Any suggestions as to what vehicles to steal this from? Reliability & availability are the two obvious issues that come to mind.

Again, I'm not looking for a normal relay, but an actual "fuel pump relay" that senses when the engine quits and shuts off the fuel pump.

Thx
Scott Kelley