I'm interested in building one of **** Upshurs horizontal hit and miss engines. It is described as having a 3/4" bore x 1" stroke, with 3 1/2" diameter flywheels, and I'm pretty sure it uses o-rings for piston rings. Here is a picture of it. I am not certain which engine it is, and I don't want to order the wrong set of plans. Can someone help identify which engine this is, and where I order the plans from.---Thanks---Brian