Yeah, Runmasters were early models and produced by Kinroad. They're good machines.
I think your connector is actually a 9-pin (with 8 wires). If your chassis harness is fine, my 9-to-6 pin adapter will help. It's universal, so you may need to swap around pins. I'm here if you need help with that.
9-to-6 Chassis Harness Wiring Adapter
https://www.buggydepot.com/product/6...g-adapter.html