This is from the Saito booklet in the box Saito 40a From the prop hub face to the center of the front mounting holes dimension H- 46mm (1.8110"). mounting hole front to back on center dimension B- 15mm (.5905"). Mounting hole patern width on center dimension A- 38mm (1.4965") Crankcase width (width between engine mount bearers dimension G-31mm(1.2205") I might be off on the conversions just an RCH, I hope that helps.