Intercooler specs please?

[weebyf15]

Happy Thanksgiving; I have a question that's been bothering me. I own a 79 P337H with American Aviation Intercoolers installed in the late 1980s. My question is; all of the POH supplements they provided me show operating limitations and placards of Normal Take-off power-32.8 Hg MAP (Standard Sea Level Conditions). Yet my actual aircraft Placard says 35.3 Hg MAP. The 35.3 agrees with my research across this forum; but why the difference between what my supplement says and the actual aircraft Placard. Bottomline question; What should I be using?? In my aircraft, if I apply full power at sea level, I can easily exceed both max RPM (2800) and even MAP of 35.3. Why the difference with the supplement directed placard label and the actual one in the aircraft?

121 EW P337H owned since Aug 2018