A friend of mine is building this engine. I modeled it in CAD for him. One of the major changes I made was to make the base out of aluminum to simplify the building process greatly. If I recall, Doug soldered everything together, and then went back and machined the base to square it up where needed.
I met Doug at Cabin Fever at the last one, two years ago. This engine an his others were all running there. There was another fine example of one running too.
It's a nice engine to build. We made other variations too. Mainly in head contruction), but essentially followed Doug's plans.
Sid