'90 Ford 7.3 will not fire

I have a 1990 Ford F250 4X4 with a 7.3. The truck has been setting for a couple of years and had not used it on the farm. I was needing a extra truck awhile back so I thought I would get it running. New starter, 2 new batteries, new electric lift put and I can't get it to fire at all. I am thinking that there is low or no combustion pressure. The truck has a little over 300,000 miles on it doing farm jobs and pulling goosenecks. Any ideas on getting the rings loosen up. Yes, I did the forbitten thing and tried either.
Thanks in advance for any ideas that might help or any other idea?

You probably have air in the fuel system. IDIs are notorious for return line leaks. Loosen the injector lines and crank the truck over until you get fuel out of the lines and then tighten them back up. If you use ether, disconnect the glow plugs so you don't end up with a big back fire.

Thanks, will check that out over the weekend