The RCMK K30's are awesome powerplants if properly modded. Have got the mods working extremely well and I do not cut out the closed up transfers. The closed up transfers are where the K30 has advantages over the Zenoah style open transfers. These engines can perform awesome with almost all that piston support in place. These engines look far better after 4-5 gallons than I have ever seen a open transfer engine look. There is no smooth shiny worn areas you usually see. The engines look more akin to a single run that is how good they look in the bore and piston sides. The torque is very good. Where I used to run a 7016 it will pull a 7316 or a 7020 no problem. Even took a prop off a twin mono that runs over 70 and it pulled it no problem.
AC S-45,
http://youtu.be/AygvH6AEuTw
AC RAZOR,
http://youtu.be/FSCIOO7w47M
AEROMARINE CONQUEST,
http://youtu.be/WUToLZyqL3Y