i built the vertical Upshur engine , and yes its a runner ! now i would like to build the Upshur Twin . i would like to stay close to the original design , have laps , o-rings for a .750 dia. piston . but i like your cam arrangement , would you consider sharing ( or selling ) your drawings . this will be my second engine build . i used a Roy Sholl CDI ignition , plan on using one on the twin , with a distributer like yours . thanks john