Well, the SX-H piston will not work in the FSR. The top of the SX-H piston is about 1.5mm or so lower (or the wrist pin is higher) than the FSR piston. Also, the bottom of the skirt hits the crank's counterweight (that would be easy to fix). I can sell the piston to recoup most of what I paid.

So, what would happen if a portion of the top of the case was milled down so that the sleeve dropped lower into the case? What all would be effected by doing that?

Or, if you machined the head so that it extended deeper into the sleeve? Wouldn't this be the same as raising the top edges of the ports?

Or, maybe half of each?

I really appreciate all of the great info that has been posted in this thread.

David