HEI relay install(PIC\'S) I installed a relay to power up my HEI today. Pretty easy install. I also installed a relay for my heated o2 sensor. Here are a couple pic's. ALL the pic's can be viewed HERE The relays I used.rated at 40 amps.They are DPDT(Double Pole Double Throw) relays.$3.00 each at my local electronics wharehouse. Ran these wire from a existing IGN. splice at the IGN. switch to trigger the relays on. Here is the splice I had made at the IGN. switch(kinda hard to see) I replace my existing 1 wire o3 sensor with a 3 wire(heated) o2 sensor.Here is the retrofit harness. Here's the new 3 wire o2 sensor installed in the drivers exhaust manifold. This is the power feed to the relays.Red goes to the HEI relay(12g wire).Blue goes to the o2 sensor relay(16g wire). The circuit is protected by a 12g fusable link(light blue wire). All hooked up now. Here's the voltage now being sent to my HEI coil 14.12volts. Should produce a nice arc! Took me an afternoon to do this project (pissed around alot though) and maybe $10.00 in materials.