With no P/S, I tell you what I'd put on it. I'd put Magnum manifolds on it. I'm not 100% sure they fit, but I think they do. Maybe someone that's done it will chime in. The big outlet Magnum manifolds outflow the 340 manifolds.
I believe they do fit, there is a thread. I believe it takes a cut down steering column and grind on the drivers side manifold some. Maybe a few shims on engine mounts.