Engine wont Start.

I have a 1992 Chevy Caprice 305 V8 with 138,563miles. I recently started experiencing coolant loss, and it was determined that I had a leaking head gasket. I changed the head gasket myself, however the process took me a few days because I didn't really have the time to do it all at once. After I put the ne gasket onto the engine and sealed everything up, I tried to start it and all I got was a click from the starter.

I thought maybe the starter was bad, but then I tested it and that turned out not to be the case. I tried to manually turn the engine, only problem is that it wont do a full rotation. It turns all the way with the exception of about 2 inches.

I originally thought that maybe I had left something in the cylinder when I was replacing the head but I've already checked that. So now I'm at a loss as to what could be causing the problem. Any help would be appreciated.?