Try rotating the engine by hand and see if it tightens up. If you can turn the crankshaft two full revolutions there shouldn’t be anything hitting each other and the engine is okay to at least crank if it won’t start. There is also a timing kit that can be found for pretty cheap if you want to verify timing is correct before cranking over especially if you already have the valve cover off. There are plenty of videos on this forum and other places that go over the timing of these engines. It would be a good idea to read the dtc’s and see what have set and gave the previous owner the idea there was a timing issue.