In my experience there is only enough material right at the end of the port on the intake manifold, the runners going up to the plenum are pretty thin. All you can really do is port match the ports, but be warned, it makes sealing the intake more difficult. I have never understood why there is not a better selection of intakes that match the ports of a 4v head. The Blue thunder is almost unattainable, the Offenhauser 360 is really wide open inside, (no port velocity), and most of the "real" Boss intakes are a goofy spread-bore. I have always hated the port mismatch of most of the popular Cleveland 4V intakes. Not to mention, very few fit under a Ram-Air hood!!! Good luck!!