It would only spin a 12x7 at 11,300 RPM with Coolpower 10% and overheats with any larger prop.
I understand that it really needs 0% nitro but will run ok with 5%. I have a Fox .50 and it runs hot with 10% in the summer, runs fine on 5% all year round. Same with an old ASP redhead. There are some head button mods to allow it to run on higher nitro. But just lowering the nitro content should get it close to the Eagle III numbers. You might do a search on a engine showdown of 6 .61 engines on the MAN website. The Fox won the battle but they had to run 5% fuel and a Fox plug to get it to run right.