Blaine got you covered with some good diagnostic vids:
Its an old sled and has been sitting, most likely has had rotten fuel left in it several times in its past. So... your entire fuel system should be checked and cleaned. Start with flushing the tank and fuel pickups and look over the fuel pump. Replace any fuel lines in the tank and on the pump that are cracked, bad or getting rotten. Same goes for the rest of the fuel system, injectors too. Check fuel pressure with a gauge (~35 lbs I think?) when you are done cleaning/replacing rotten lines.
Be thorough and you will win,
Don't be too concerned with the stuck oil pump lever at this point. I have seen them stick open after sitting a long time. Every one that I freed up with a bit of lube on the return spring and shaft, were fine after that.