That sounds like a conventional head reconditioning job from a quality machine shop. In the racing business, "Stage IV" in reference to a cylinder head usually involves porting, polishing, flow-marching ports, oversized valves, and a few other specialized procedures reserved for competition-only engines. If you do those things, and install a very radical grind racing camshaft, it might be possible to make two Rochester B's function close to effectively on a 235 engine, but only at wide open throttle. Even then, it would be difficult to get any sort of good performance and/or acceptable fuel economy during low speed or part throttle operation.
Jerry
