As my friend used to say, "We agree that we can disagree!" I don't put much faith in Comp's specs. Look at the valve lift...they computed this with a Chevy rocker ratio of 1.5:1 rather than IH's 1.6:1. Comp lists 800 rpm as low operating range...that's basically idle. I have a Scout with a 392, 3.54 gears, 10.50X31 tires and a 4-speed and I can start off from an idle in 4th. Can't get any better than that! What they consider their "power band" is arbitrary. I have not seen any standardization of these numbers or how they are calculated. How do they arrive at these numbers? If you compare duration of these cams, the Comp has higher degree duration at .050 which usually means it is a higher RPM cam. LSA is the same at 110 degrees so overlap, in theory should be the same but may be longer in the Comp because of the longer duration. I have used Comp 252's in the past and haven't seen much difference compared to Isky. I've also used the Comp 260 and power was good but mileage was in the toilet! Years ago, Isky told me that they build in 4 degree advance to compensate for the emission timing gear (R1 vs R2) on flat top piston IH's. I tow a 5000 pound trailer in Montana with no issues. Also, all my motors run between 8.7:1 and 9:1 compression. Maybe that makes a difference as does the gearing and transmission. All three of my 1210's have 5 speed-OD's which are lousy towing transmissions but my Scouts are divided auto and 4 speeds and do well. I have one Isky 258 (not in their catalog as Ron ground it for me special) that I really like but I can't recall the lift or duration. I guess choice boils down to a number of factors and personal experience.