[Northwest Outlaw]

I'm new to all this wiring stuff, but i have done some research and problem solving. If there is a thread on this already please direct me, i couldn't find what i was looking for.

TRUCK: 1961 with a 1971 small block, using a new '63 front harness because of the alternator hook ups, purchased from ClassicParts.com. The alternator is new.

SITUATION: Alternator is not producing a charge. I've tested this by using a multimeter to read voltage output from the (+) post on the back of the alternator; it reads the same as the battery, about 12v. I've also pulled the negative cable off the battery while truck was running and it died. So, no charge coming from the alternator. I got the same readings while at idle and high rpm.

WHAT I'VE DONE:
1) Tested the alt. at the shop where i purchased it only a few months ago. It's a small mom and pop shop, not a national chain. We tested the alt as well as another one off the shelf and got good readings. So the alternator can produce charge, it just isn't while in my truck.
2) Checked and re-grounded all ground connections, made sure all mounting hardware for the alt brackets, regulator and relay were clean bare metal. Using one 1/2" and one 1" ground strap from the block to the frame, both bolt to bare metal. No change.
3) Replaced the voltage regulator and horn relay. No change.

IDEAS OF THE ISSUE:
-wiring harness is defective and not allowing the regulator to activate the alternator?
-something in the cab wiring is causing interference?
-....i have no other ideas, that's why i'm asking you guys!

I would like to figure this out so i understand what was causing the problem. I know i will hear "Get a single wire alt", but i would really like to know what's up.

Picture is before and after of the front harness, regulator and relay. I can provide more pics of something specific if it will help

Thanks for any help