Recently installed a new clutch cable. When looking at the the pull on the fork on the transmission, how far should the fork move? I was estimating about 3/4” to disengage the clutch. However when I had the car running there was no way to get the car into gear, grinding only. Cable is taught, do I have to tighten it down further or look for something else that might be causing my issue.
Haven’t tried tightening a second time as I melted my alternators wiring during the first start and shut her down. On a side note, new harness is ordered, was going to make my own decided 914rubber had a decent deal on harness which included plug ends and grommets. Hope part arrives and have her up to try again his weekend and take it for a spin.

Examine the firewall where the clutch tube is brazed in, as it's a common failure point. The metal can crack from stress and flex everytime you push the clutch pedal. Have someone push on the pedal while you look at it.

Do you have two nuts at the trunion? It's an odd size and originally had a nylon insert nut. By now the nylon insert nut won't hold and it's best to have a nut with a jamb nut. I think it's M7x1.0

The roll pin in the pedal cluster can fail, but typically you'll loose your clutch altogether.

The manuals say that clutch adjustment is done by checking the pedal free travel. I just like to take the slack out at the throw out arm. I loosen it to the point where you can push the cable, and then tighten it up until the cable is just taught without moving the arm. When you have the slack out of the cable, you move the pedal stop to increase or decrease travel until you don't get gear clash.

Here's a good thread on the subject:

Dr. Evil on clutch cable