this is the OE 1968 (early) system with the box reg in the pic & an alt with either 1 field terminal (69 & earlier) or a later alt with 2 field terminals & if so then one of them has to be grounded right there to the alt case. With the alt/reg good (assuming the reg is grounded well to the firewall) that only leaves the field wiring. check that there is fire to the blue wire (ign) side terminal on the reg with the key on or jump fire directly to it from the batt positive terminal or the starter relay large "batt" stud & see if it will now charge. If not switch the ign off then take off the green wire off of the other side of the reg and on the other end of the green wire at the alt pull the female connector off of the field terminal & connect the two with a jumper wire & restart it & see if it now charges. If the alt is good & has 1 field terminal with the green wire on it or 1 of the field terminals grounded if it's a later alt & the reg is good & the reg is grounded and the "ign" side of the reg has fire and there's continuity between the reg "fld" terminal and the alt field terminal via the green wire then it MUST charge. Holler back when you can. EDIT To check the continuity of the green wire an easier way would be (ign off) to disconnect the green wire from the reg "fld" terminal & then start it & jump fire to the green wire (not the fld terminal) for 3 seconds max & see if it charges (fast idle)