id pop a valve cove off and see what the valves are doing
any chance you could have the rockers to tight, that would hold it back for sure, maybe back off the rocker bolts and see if it tuns easier by hand," don't start it like that" it will bend a push rod or something for sure.
and come to think of it, did you lube the crap out of everything when you installed cam and lifters? soak the lifters in oil over night? and crank it with the plugs out to build oil pressure?
just asking, don't want to piss you off with obvious questions. i'd have maybe 3 or 4 hairs left if i were you right now....
