My latest projects/ experiments have been titanium wrist pins for the Go engines. They would work on other motors but on the Go they tend to wear the pin and the piston due to the fit not being tight enough from the factory. (they may be tighter on the new Gx series) So I made a titanium pin slightly larger to make the fit tight again, this almost needs to be custom to each engine like during a rebuild.
I also have been putting a dome shape in the backplate for a little more case volume on some engines.
I also have 5.5 and 6.0 restrictors ready to ship, I'll try to get some pics up this week. They are $13.00 each.

Rex