I have a 86 pickup with efi and i keep blowing my 80 amp fuse in the engine bay. It blows if i drive the truck more than 30 mins. Where do the wires go from the fuse so i can check?

 

Well, Buss B feeds many other circuits but a couple of the largest current draws would be the alternator, cruise control, and heater circuits. 1st thing I would check is have the alternator tested for a possible short condition after it gets hot.