i have a 98 251 with a 540 ci. i run a 26 pitch bravo at 79.2 mph and 5600 rpm. need a 28 pitch. for the bounce mine did the same thing from 30mph to wot, it sucked so, my buddy and i came up with a solution, we made a wedge out of a certain kind of material (top secret,haha) and put them on the most outer edge of the farthest chim at the back. and it cured it 100%. mine was really bad, the boat would actually jumped out of the water. all my buddies have 253's, 259's, and 270's and they all did it, untill we put these on. and NO believe it or not it did not hurt the top end speed. to be honest it feels like it lifts the rear, and airs the boat out more.please becareful with your dry header set up. you are putting alot of heat in that engine compartment that cant excape. i dont want you to have a fire on your hands. it has happened before. if your interested in what we used let me know and maybe we can hook you up with them for a small price. they will already be cut to size, and the right height.