They look a reasonable set of castings. I made this engine from a Hemmingway kit some years ago, but I notice they no longer list it. I have the set of drawings in A2 size, so not easy to copy, but if you have no success with obtaining a set, I am sure we can find a way for me to copy them. If you are serious about making it, I also have the table of off-set figures for milling the cams. These were produced using the Cam-Calc programme, originated by Rod Jenkins, a frequent visitor to this site.
Keith.