first make sure the marks line up, slap a stock cam gear on it just for reference to line it up. also question how the msd is wired, also do a cylinder leakdown test and make sure them valves were seated . if it is choking (200 rpm lugging) ,make sure your fuel regulator is vaccumed to the manifold and the map is tubbed to the throttle body correct port. if that fails, read some mary poppins.