On my 66 Valiant, it had a 170 and swapped to a 340 and used the same wiring harness with no issues, only spliced some wiring in for the aftermarket ignition is all
Yup, the only two wires that are different are the oil sending unit and the coil wire....both are a bit longer than what is needed. To make it look like a V8 harness, just fold those two wires back against the harness and re-wrap the outer tape.
