little more back ground...with my 37 GMC 1/2-ton truck i changed out the motor and trans to a 1946 chevy 216.5 engine and 3 speed. The harness I bought was from Classic Parts USA. The part# 52-015, (1934-39) Wiring Harness-for a Generator. I also installed a voltage regulator. The harness instructions were somewhat limited. I found a drawing online.