Replacement 5.9l Piston Recommendation

They are referring to max RPM and HP they are rated for and are for a non boosted or juiced application. They look very racy and are inexpensive so they dont want claimer guys ringing them to 8K or using them on a 250HP nitrous shot. They are great for anything with a cast crank as they will both crap out at anything over 7500. It doesnt mean you cant go play at the strip on weekends, just keep the R's respectable and no power adders. You should be very happy with them.