Yes, you are right, the power valves do represent quite a bit more fuel. I used to start 10 sizes higher on secondary jets and drop down two jet sizes at a time till I felt or heard a bog, then go up one size at time on Holleys with the seconday PVs plugged. I always assumed at the time that the customer or previous owner had done it as the most of the customers stuff had leaky float bowl gaskets and plier marks on the bowl screws LOL! The link I posted for the exploded diagram does not show plugs, but these are, of course generic and may not apply to some of the older Holleys. Have a great weekend!