How do I go about starting a truck that's been garaged 4-5 years?

I have a 1973 GMC 3/4 ton Suburban, 350 V8, pretty much original engine aside from tune-ups and timing chain. Ran ok when I stopped driving it, now that I have accepted that gas will never be below $2 a gallon might as well put it on the road. Often used STP additive in the fuel but don’t remember if I did last time I put gas in it years ago. What/how should I go about starting it up so I don’t do any damage? Please spell things put for me if you reply, I’m fairly mechanically-challenged.

The frist thing I would do is change the oil and filter. Then put in 5 GL of gas with a good additive. Then give it try. I will bet it will start and run. When you get it running then change all fulids. If you see clear water when you change the oil, dont worry its just condisation. I have seen this tractors that were stored for 2 or more years.

I would disable the ignition so that it won’t start

Crank the engine a few times to build up oil pressure

Hook up the ignition so that it’ll start

Turn the key to run position and hope for the best

I’m in agreement with @oldbodyman . . . change that oil and filter and add some good fuel

One more thing . . . charge that battery, or hook up a fresh one

If it doesn’t start, it’s probably the fuel

Gasoline tends to degrade after some time. If the gasoline smells rancid, there’s your problem

I’d be inclined to first remove the spark plugs, squirt a little oil into each of the spark plug holes, and crank the engine slowly by hand several rotations, putting a socket wrench on the crankshaft pulley.

You didn’t mention where it is. If it is in Arizona, you should be fine. If it is in Louisiana, you could have a valve rusted open, making GeorgeSanJose’s suggestions vital.