Chris on the AE 21253, floating is kinda a waste of time, ask me how I know. The AE 2153 has a fairly large slipper on the side of the piston and and a much shorter piston pin, if you try to just use a teflon button with the suppiled pin, you got way too much distance to get back to the cylinder wall and a risky set up if you ask me, the race pistons (JE, Venolia, etc.) either are full circle pistons are have samller slippers on the side. I floated a AE21253 with longer stock pins and made custom teflon buttons on a LP/HP SCCA engine, but the piston weight increased with the longer pin, it worked fine but was a PITA, in my opinon if you're going to use the AE21253 piston just press fit it and get the advantages of the shorter pin and less weight. By the way, the AE21253 is the same piston as the AE21251 except it has less oiling slots in the oil control ring land area, thus more meat holding the top and bottom of the piston together and a good candidate for racing with a off the shelf piston, it's a tough little piston that doesn't cost that much, you just limited to what you can do with it, as long as you don't go over about 12.0 to 1 and keep the lobe lift at .350-.355" with zero deck, you will have tons of valve clearence and be fine. If you end up going with a floating the stock rods, conatct me, I've got a slick deal for that and it's a ton better than what most are doing.