Heat Shield Placement?

Very few manufacturers used exhaust manifold gaskets in the old days. Back then the exhaust manifold and head were both cast iron with pretty much the same expansion and contraction rates when hot or cold. Gasket are only used where either the materials are of a dissimilar material ( aluminum/cast iron ) or different surface finish. If your heads are true and your exhaust manifolds are straight, you won't need a gasket . only thread sealer on the outside exhaust manifold studs/bolts.