My boat is now hitting the rev limiter with labbed 24 hydros on 496 mag HOs at aprox 5200 rpms with outside temps aprox 60 degrees F. My gut feeling is there is another 50-100 rpms left ? Temperatures heat up another 20 -30 degrees in Summer and some loss of horsepower is expected. Anyone know typical loss of rpms in Summer? Maybe wait and see before adding cup to reduce rpms?

I lose as much as 200 RPM's in the heat of summer on my HO's going from 60° to 90°. You may want to consider a second set of props. Also, spinning faster doesn't always mean you go faster. My boat was happiest when propped to 5050 RPM.

Thanks, Maybe I'll sit tight for now with the 24s and add 1" cup next winter. My spare props are 23s so maybe I'll sell them and get a set of 25s in the future. My 23s are perfect cond. if anyone out there wants to trade for 25s?

rev limit on stock ho is 5150rpm