I don't have any HP goals. This is a temporary engine to get me by while I build something bigger and get my frame tied ect. I understand the bigger port and I have a set of J heads sitting here. But I don't have fuel injection to squirt the fuel down the port so I'm hypothesizing that a smaller more efficient port would move air faster and atomize my fuel more efficiently at low RPM. I have used Rhoads lifters for 40 years to tame street cams but this is only my second attempt to use them as a VVT system at low rpm for mileage on a mild street cam. The other time is my current 273 with a 220 at .050 cam. So far it's working well considering I have a rich carb. I'll address that soon. Let's approach this from another angle. If I get a set of 920's to flow similar to J heads stock how will the smaller ports negatively affect my performance from a mileage stand point?