Firewall-Forward wiring harness w/ cannon plug

[bdjohn4]

As you can see, my wiring harness looks its age (about 42 years) and it is time to be replaced. A local shop says they can build one easily but would spend considerable time researching the required spec of the wire. The wiring diagram doesn't apparently go into the actual spec of the wire.

1) Is there there a source for these harnesses?

2) if no source and a custom build is required, is there a source of an engineering drawing or something that anyone knows about.?

Thanks in advance.

John ('69 E-model)

[N601RX]

The Mil Spec number for each wire is listed in the parts manual.  Some of the Mil Spec wire numbers have been superceeded by newer numbers.