You will need to connect a timing light.
Locate the timing marks on the crankshaft pulley, and timing marker on the timing cover. Paint the marks on each with a light colored marker where you want the timing to be set.
Locate the spout connector and remove it. I don't know were it is on this particular truck, but it is usually close to the distributor. It is a small square connector looking thing in one of the wires. Maybe someone that knows will be more exact.
Loosen the bolt holding the distributor enough so you can turn the distributor by hand with some resistance. Not so loose that the distributor will spin when the engine is started.
Start the truck, aim the light at the marks you made previously. Turn the distributor slightly and you will see the mark on the crankshaft move. Set the marks even with each other.
Stop the engine, replace the spout, retighten the dist bolt, and you are ready to go.
shady