Have you tried unbolting the two halves of the fuseblock itself,where it passes through the cab???.I have seen many here that rusted the connectors right out on the inside of the fusebox,but outside everything looks preety good--it might be all gangreen in there.If it wont crank,no power to anything,lights,etc,its probably in the circuit that comes from the starter solenoid,the red wires with the fuse links in them,at the firewall there is a junction block near the brake booster,one of the red wires goes there,and the other goes into the harness behind the motor(a real pain to get at)and eventually goes into the fusebox to power everything in the truck.Its probably in that curcuit--but on an old truck it could be lots of other reasons.The fact your not getting power out of the altenator (the BIG red wire with the nut,not the little wires on the plug,I am assuming)means there is no power getting from the wires on the solenoid to the fusebox and the rest of the truck.Good luck--having a 74 with a gangreen harness,I'm gettin to know all the wires and color codes alot more than I care to Know!!. /forums/images/graemlins/blush.gif