brake light troubleshooting

[SS317]

I have a 66 that I have replaced almost all wiring with new stuff from classic parts. I'm stuck and need a little direction.

I have blinkers all the way around, and running lights in front, not in back. No brake lights in back.
I know there is a hard short somewhere, the brake fuse blows as soon as I put a fresh one in.
Fuse box is new, all light wiring is new, headlight switch is new.
I unplugged the connections near the gas pedal to help isolate the short. I unplugged the steering wheel curved connectors to help isolate. I still blow the fuse as soon as I put it in. I have wiring diagrams from the site here and I don't see what else I can do to isolate even more.
Any thoughts?