Yes, those are the mounts that Don Stegall was selling. I have two of them and work very well. I can easily switch out from my Q-25 engine to my 424 engine. I am going to try to purchase the remaining stock so that I can make them available to interested Q-25 guys.

The Magnum 25 XLS will work with the standard Viper backplate mount because that engine does not have a rear needle valve. However, the OS 25FX will not without hacking a big chunk out of the mount to clear the needle valve. Another option is to cut off the needle valve mounting bracket from the backplate of the FX and use a remote needle valve mounted somewhere else that does not interfere. http://www3.towerhobbies.com/cgi-bin...&I=LXCR44&P=ML