Hey duck two things here.
1.dont be upset ok, but the OS 46 AX with stock muffler will turn a APC 10x7 at 13,800 on 15% fuel all day long.
2. when you get the Blue muffler from jett you need to have it propped to turn no less than 14,500 and no more than 16,000 with the blue one ok. The red Jett muffler needs to be no less than 15,000. These numbers are for the muffler to do its best. Yes it will still work below that rpm but not at its best tuned range. The 10x8 and blue i think should be right around 14,800 -15,000 if i remember reading right. Now also note i have never owned one of these but basing my info off of what huys have posted. As far as the tuning range of the Jett mufflers they are based on my own running of many different engines.

One thing for all you guys to look out for on the Jett mufflers on the market is a Jett "ss" muffler. this muffler on supertigers and a few other engines is extraordinary. i will gladly pay double the price ofr one of these mufflers if you guys find one. Dub broke the mold on these so these are the "real Gold" mufflers lol. If you ever want to know the reason these are so god shoot me a PM and i will explain for you.