i threw a rod in the d16z6 i had, so i bought another block and put the same z6 head on it that i had before. well i finished the swap but when i crank it over it cranks some then becomes stiff then cranks again but wont start, i turned over the crank with a socket too and it felt really stiff for about half a turn then went very easy, i wasnt sure what could be happening? my timing is right too

 

When you turn it over by hand take the plugs out and it should get easy.