flat 70 & up reg/2 field alt system correct? Confirm that the reg is grounded but if I am reading this right it started when you did the Madd bypass? so I will assume the reg is grounded but do check it. Also assuming tha batt is fully charged (it should be by now ) and that the batt is good (not sulphated/bad cell). Take off both field wires from the alt and take off the triangle green/blue wire connector from the reg. with some jumper wires jump 12V to both the reg top (blue wire) terminal AND to one of the alt field terminals and with another jumper connect the other alt field terminal to the other reg (side) terminal (the green wire circuit) & see if it charges normally at a fast idle. If so this tells you the hard components are OK & that it is a wiring issue. Holler back when you can and if this is an earlier setup (box reg/1 field terminal alt or 2 field terminal alt with 1 field terminal grounded) holler back. Most overcharging is a bad or not grounded reg or a grounded brush assy on the green wire side or the green wire/its end terminals grounded). Easier yet since it stops charging when you pull the reg triangle connector you might pull it then jump fire right there to the blue wire reg nub terminal & if it still overcharges then find where the green wire from reg to alt/green wire brush assy is grounded or a bad or not grounded reg. holler back. EDIT this ain't resulting from the Madd bypass but it sounds like all that other major wiring changeover was done at the same time (when the problem started). & also holler if this is the earlier (box reg) setup