Danny,
After getting similar advice (here) about using an oil pressure switch, but no information about which switch, I checked out a wide variety of switches.
"Any of the fuel injected Chevy V-8's will have a 3-pole pressure switch that mounts in a threaded port just above the oil filter. Two of the terminals are the normally-open fuel pump switch leads, and the third one is a ground for the oil pressure idiot light."
I had to try several two-pole and three-pole switches before I got one that switched appropriately for this application. It switches on at about 4 psi (rated to switch on at 2-8 psi).
NAPA: MPE OP6626SB
I have this now working to control two Carter-Weber Motorcraft 740 2-barrel carbs on a 6v 261 engine. You'll need a T-fitting in the oil-pressure line location. I get the hot lead from the voltage regulator (I wanted a source inside the engine compartment).
