the shop manual
details adjusting the reg, just have to set the kick in/out points up 2 volts - I think folks here generally feel it's not a good idea to run the gen/reg at 8V when it's designed for 6 .... you could always use the 8V battery with the system as-is and put the batt on a charger once in a while - assuming you're just working on the truck, not aiming to use it regular
Bill
