'72 C-10 Electrical Problem

[C10 - C90 Bill]

Jumped into my '72 C-10 today, turned the key and nothing. Not even an idiot light on the dash. Checked the Battery, no. Checked and cleaned the Side Post terminals, no. Checked and cleaned the Neg Ground to the block, no. Looked for any defects in the wires, no. Call a mechanic buddy and he told me that the Cables can corrode from the inside. They are 50 year old originals. Decided to go ahead and change both.

The Negative Cable is about 24 Inches long, but noticed that the Positive Cables come in different size lengths.

I've got a '72 C-10, 307, 3-Speed, no AC and a Side Post Battery. Does anyone know what length the Positive Cable would be?

Here is the listing from LMC:

https://www.lmctruck.com/1967-72-che...junction-block

By the way, I did wiggle a lot of the wires in the meantime. After cleaning up the tools, I decided to give it one more try and it started!! I said, boy am I in trouble now, lol.