before i replaced the screw with the nylon it would blow my fuse on my field wire ( power to the brown wire after the switch) I originally replaced all 4 screws then found a thread on the forum that said it was to only be 3 of them. Before with the 4 screws replaced i preformed a magnetic slap test. i was getting nothing. Then replacing the the 4th screw with the metal screw i then had a magnetic field when the key was in the on position. i have not blown a fuse since replacing the screws. I understand that I need the reg/rec Grounded or else it will not work and i will receive full charge from the stator with no regulation. I am going today to check the reg rec to see if it is good. I had a pretty long talk with gary about weather i need to replace the screws and did not understand why i was blowing a fuse if they did not need to be replaced. It is in the thread above.If you are using the same aftermarket reg/rec as linked to in that thread, a correct unit for the '79 and older alternator, then you don't want or need to install the nylon screws. On the older alternator, the inner brush is grounded full time (through it's mounting screws) and the outer brush is fed regulated power from the regulator. So, positive in through the outer brush and negative out at the inner brush. This completes the circuit. By installing the nylon screws on the inner brush, you have isolated it from ground and the circuit is no longer complete. You will get no charging output.
You must connect the black wire from the new reg/rec unit. It is the ground wire for both the reg and the rec.