the basic answer is correct , the heads actually will bolt on & have the same bolt pattern but that is about it , the upper row of head bolts sit under the intake ports & have to have studs down into special bosses in the block to tighten them
second the block has to be notched to allow clearance for the pushrods
third there is no provision to get to oil back out of the heads , hemi blocks have extra drain passeges to get the oil back into the oil pan on the front & rear of both sides of the block otherwise you will end up with a coulpe Quarts of oil under each valve cover submursing the exhaust valves & springs
no clue on the interchangability of the New Hemi heads onto a small block