The AMSOIL 20W-50 that you have been running is an excellent oil and there is no need to change to the AMSOIL Dominator racing oils. The AMSOIL Dominator racing oils are designed for racing only and do not carry any API or OEM oil specifications. The WIX racing filter 51061R is an excellent filter for the high RPM’s you are running.
So, you're saying the 5000rpms that these boats run for long durations at a time, do not classify as racing? Listen, my family has been selling this stuff for nearly 30years, so I know damn well what I am talking about. If you want the best protection and performance, you use the Dominator line, specifically the 15w50. It has the best additive package in the AMSOIL line, and was specifically developed with Bob Teague for his 525's in his skater. Just because it says "racing" on it, does not mean its not good for longevity. I have, and have at least a dozen customers, that have ran this oil specfically for full seasons, which is in the range of 65 hours, and the analysis reports still show the oil to be good for continued use.
