Ditto to all the above comments. Bar the engine over a few turns with a big pry bar in the flywheel ring gear teeth to be sure you don't have a cylinder full of rust, and maybe fog a little penetrating oil into the intake while you're hand-turning the engine, and it will probably crank right up.
One problem with Detriot engines in general is a tendency for the fuel system to lose prime if they sit without running for a while. The low-pressure fuel transfer pump will not self-prime by spinning the engine over with the starter, or even towing the truck to spin the engine. Most Detroits have two fuel filters, a primary and secondary unit. The secondary filter will have a threaded plug between the inlet and outlet ports, where you can install a nipple to attach a piece of rubber tubing. Borrow an electric fuel pump capable of supplying about 5 lbs. of pressure or so, plumb the pump output to the center tap on the filter, and use a long piece of tubing into the fuel tank to supply the electric pump with fuel. Run the pump for half a minute or so to get a solid stream of fuel flowing through the transfer pump, the injectors, and back through the return line to the tank. When you can hear return fuel dribbling back into the tank, the system is primed. Shut the pump off, remove the nipple and plug the port in the filter housing, and fire it up! Remember the warnings about being sure the fuel rack is free to move, and the governor linkage isn't stuck in the full-fuel position. There is a shutdown lever on top of the governor housing, sometimes operated by an electric solenoid, other times, it might be air-operated. In an emergency, you can move the shutdown lever by hand, or pull the emergency shutdown cable which strangles the air intake. Shutting off electrical power WILL NOT stop a Diesel engine!
Jerry
