I have a 350 bored .060 over, a comp cam 280H, flat top pistons and 58cc 305 heads that have been polished and ported, and the block has been decked .010.  I recently purchased a set of comp cams 1.6 roller rockers and dropped them off at the engine builder.  Now he tells me that when he installed them the engine won't turn over and he didn't take the time to figure out why.  Does anyone have any ideas what is or could be binding in the engine?  

could be piston to valve interference due to the block decking killing valve clearance. Could also be rotating assembly problem.I would find a different engine builder too.Sounds like someone made a boo boo.  

i agree with mav....sounds like some incompetence is afoot  

You've got small 58cc heads, a shorter deck, flat-tops, and a big cam.  I'm thinking piston-to-valve interference.  You should kill your builder.  

bad deal. remove all rocker arms and try to turn motor over. if it turns over more then one full turn the problem is in the top end, valve to piston most likely.
if it does not turn over more then one full turn it is a rotating assembly.  

And then, kill your builder.