Yes, but you did notice I said "unless there are retrofits out there". Of course you would agree that you get less fuel burn, because you are making less horsepower, wouldn't you? It's no misprint, to get 350 horses out of the TIO 540, you pretty much need 2575 and 42" You'd be getting something in the region of about 300 to maybe 310 hp at that rpm. Check the lycoming engine handbook that someone mentioned earlier. It'll show you the hp you are producing. If I can find it i'll have a look at it tonight.