motor wont turn over?

There's only 2 physical possibilities . Your pistons are contacting the exhaust valves or the plugs. The only reason the exhaust valves would hit the pistions is if you have a hi lift cam and the cam is way out of sinc. I guess it may be possible for the cam to be out of sinc enough that there is too much static compression at tdc of the compression stroke.

This is easy to do if you have a timing gear set with multiple keyways. Did you degree the cam?

It sure is sounding like a timing chain that has jumped a few teeth. Are you getting any puffback out the carb?

The other one is more serious and requires more work. If your exhaust valves are contacting the pistons there has to be a reason. Hi compression pistons,hi lift cam,milled heads and or block all come to mind.
Did you check piston to valve clearance?

Valve spring coil bind is a possibility too..