ressurecting a sleeping beast..need help/advice

If it has a carb on it? Should not be much except water, and THAT can be a problem. A REAL problem

so where was it? Was it uncovered? No carb? Could it have gotten water, etc insideZ?

If so, you REALLY need to START by pulling the intake, and if the runners show evidences of rust/ debri/ garbage THEN you need to continue and pull the heads, too.

However, if it's got a carb on, and was not exposed to water, there's probably nothing down there. In that case, I'd pull all the plugs, leave them out, squirt a generous amount of motor oil in the cylinders, and turn it over some.

At the same time, pull the oil sender and see if it pumps oil. As soon as you confirm that, drain and change the oil. Watch this carefully that it recovers oil pressure after the change. I would NOT change the filter at this point, due to priming problems. After (if) you get it running for a few hours, THEN I'd think about changing the filter and the oil again.

Don't trust any gas in the tank, and don't trust the antifreeze.