wow 4 years. Sorry friend, try not to spend to much money on that truck. Chances are the rings on the piston has rusted there self to the cylinder walls and when the engine is cranked, there going to be junked. You can try this to get the engine started, buy some Marvel Mystery OIL from Auto Zone and add 3 to 4 table spoon in to the cylinders where the spark plugs go in to and let sit for two days then try turning the engine over by the crank pulley. Also your going to need to replace the fuel filter and hope the Carburetor is in still working condition which i a kinda lean towards that it's not. Any fuel in the gas tank and throughout the fuel system will have turned in to varnish and will need to be cleaned out before trying to start the engine. Adding Acetone (old school octane boost) to your fuel of a ratio 3oz to 10 gallons of gas will help clean out the fuel system, no more then that will be need to be used and can harm the fuel system. Once that had been done, You can try to start the engine and if it does Start, give it a really good tune up Plugs, wires, rotor and cap, oil and filter and Antifreeze with a new thermostat.