The previous owner said he was driving the truck and it just died, and he never tried to get it running again. I decided to start with fuel and see what would happen. New battery and an inline fuel filter first, then I ran a line to a gas can and the truck fired right up. From what I can tell, something must have gotten gummed up in the fuel lines and he basically just ran out of fuel. The engine ran great, no bad noises or smoke.
I started going through the rest of the fuel system - the truck had aftermarket saddle tanks that were full of a water-gas mixture. I thought the original tank looked like it was in good shape so I started pouring fuel...and it filled up my shoe. Big rust hole.
I knew I wanted to have a rear-mounted tank anyway so this accelerated that project.