That's an admirable trait, but the problem is, you have chosen one of the worst possible engines to try to do that with. The narrow (small) bore center spacing of a /6 hamstrings all efforts to try to put decent size valves in the motor, and the fact that the ports were designed for a 170 (and, they were) doesn't help any. The only engine I can think of that is a poorer choice for trying to go fast, normally aspirated, is a 144/170/200/250 Ford 6, with the integrally-cast, intake manifold.
