Looking at the overall picture here, a 2x4 is worth 4 hp and about 10 ft pounds over a stock four barrel... For the price they go for I think porting the single four factory chunk may be the way to go My impression and opinion is that either the few aftermarket parts available for Nailheads are primitive, or original factory parts were very well designed and/or the engine just doesn't have much left to give after a good quality rebuild. Maybe a little bit of all of the above. I'm not a knowledgeable Buick guy, but just looking at it, the water cross over is not integrated with the intake (cooler intake charge), the intake has an "Air gap" for the same purpose, the valves and ports were purpose built for maximal useable lower RPM torque. Velocity at low lifts over Volume at upper RPM's... Seems to me the guys who designed the Nailhead did a fantastic job and used ideas that were cutting edge, if not decades before their time... Edelbrock makes a fair bit of money selling "Air Gap" intakes these days. The things have the torque curve of a diesel... Still intakes that maximize velocity might be the way to go, I would have loved to see how 3 deuces faired in the same Dyno shootout. Or a bunch of Webers... I'm also left wondering how a smaller CFM 4v like a 700 CFM Edelbrock on a fictional high rise (Victor Junior like) manifold would have compared.