...another thing that separates the magnum exhaust manifolds from the LA counterparts is the magnums have the cast center divider between the 3/5 and 4/6 exhaust ports (center ports), so using LA manifolds on the magnum heads would be the same difference as using LA manifolds on LA heads, and while I would 'like' to have the center divider...if Ma Mopar didn't consider it important enough I won't either.