Hei conversion Intermittent start?

You can buy those relay pigtails on ebay with or without relay. I bought a box of 10. For more current, upgrade the 2 main wires. You can find the relays (30 or 40 A) even at Radio Shack. Maybe even easier, you can often find a "fan relay" w/ harness on ebay. I bought 2 for $15 ea in a GM shrink package. They were part of a dealer add-on fan upgrade/recall, maybe for AZ, and hit the surplus market. The relay is slightly different (shrouded base like some Mopar ones, but same terminals - 85,86,30,87,87a).