Dar, when you get a chance, put an APC 11x6 on that engine. I don't trust the MA 11x6 as a reliable load. I saw one GMS .47 that did 12k peak on an APC 11x6 then do 13,800 on an MA 11x6 5 minutes later.

These are the numbers I have seen for various engines on the APC 11x6:

AX .46 - 12,300 rpm
TT .46 Pro - 12,000 rpm
TT .46 Pro (Tower muffler) - 12,200 rpm
GMS .47 (two piece muffler) - 11,800 rpm
GMS .47 (three piece muffler) - 12,000 rpm

FX .46 - 11,300 rpm
FX .46 (Tower muffler) - 11,600 rpm
ASP .46 - 11,500 rpm
ASP .46 (Tower muffler) 11,800 rpm


For the .50 sizes:
OS .50 SX and ASP .52 - about 13,200 rpm
ST G51 - 11,800 rpm

I have never seen an ST (including the .51) outspin an AX .46 prop for prop.