So, I bartered a Cox Medallion out of my dad in order to build a beam 1/2 A with a little more umph. I ran it today with a few experiments. First I ran it with a standard head and a Cox 5X3 she ran a fairly stable 18,500. I then switched to a grish 5.5X3 She ran 17,100. Next I used a APC 5.7X3 17,200. Then I switched to a Merlin adapter head with the hot plug. I stayed with the APC prop as I liked it the best. I started with one head gasket and it ran 17,900 - 18,200 Then went to two head gaskets and it ran a very stable 17,800-18,00. I then used three head gaskets and it went 17,700 but was unstable. So I am sticking with the APC prop the Merlin Head and two head gaskets. I need a better fitting needle valve as this one was a little loose fitting. I am tickled pink I was not expecting it to perform this well. Now I got to get building.