19 70 driver side exhaust manifold interchange
67 A-Body exhaust manifold castings are LH 2780945 and RH 2843953. 70-71 A-Body 318 casings are LH 2951123. Looks like 73-74 A-Body LH exhaust manifold, casting 3614395, would work also.
67 exhaust manifolds
73-74 LH exhaust manifold