I did an "engine database" that has specs for 267 different engines and it includes the mounting hole dimensions for most of them. I use that to see if one of these fixed rail (1 piece) mounts will work. Yea, I'm a techie (database stuff).

Seems to me that part of the mount discussion also affects what you use for a control rod for the throttle. Do you use a Dubro 4-stroke throttle linkage?