you should have removed the roll pins front and rear of block deck so they do not hold manifold up and not let it seal to heads . if you did manifold should still hae clearance under front and rear of deck when installed with gaskets or a no seal condition will happen in port area . this would be due to head milling .
look in distributor for too light of springs or maby one broken , not bringing timing down at idle causing a hi idle condition !
