'94 F250 Compound issue
 

My timing chain needed to be replaced so I parked my truck for fear of it breaking down on me in my rural area. It sat for 3+ years. Recently tried to start it, but it wouldn't fire. Yesterday someone came to look to buy and discovered gas in the oil. The engine had NO problems (other than timing chain), no skipping, etc prior to my parking it. Is it possible that the gas got into the engine from what was pumped into the system when trying to start it earlier? I want to try to get it running again, but can't afford to replace the motor. It is a 5.8 L, 351 with ~250,000 miles. Any feedback will be greatly appreciated!

A lot will depend on where it sat and what if any storage prep was done.
Gas can definitely get into the oil while attempting to start the engine if done long enough.
Two things right off the top,
It may never start with gas setting in the tank that long plus it probably absorbed some moisture over time.
What ever condition the engine was in at the time it was parked can be affected by attempting to start the engine with diluted and probably contaminated oil.
The cost of an oil and filter change and fresh gasoline would not be a total loss since the timing chain is due to be changed anyway.
Sometimes , situations like this can surprise all of us .
Brand new vehicles that sat in a warehouse for a year or two the exhaust would smell terrible from the stale gasoline in the tank.