1951 Chevrolet 3100 truck? (be sure to always mention year/size of truck).
6v harness wiring will work fine with a 12v conversion (6 uses larger gauge wiring than is needed for 12v).
The most original kits you can get are the cloth-braided kits sold/made by many vendors: $$$
Excellent, much less expensive kits (~$150) are available - Chevrolet changed to plastic in 1953.
Jim Carter, Classic Parts, and Chevs of the 40s sell nice assemblies.
These kits include extra wiring for additional tail lamps and for signals (you would need to buy inexpensive two-filament adapters for the front parking/signal conversion).
If you need links, let us know, after letting us know the style you want.
