You will also need an unserviceable crankshaft to go in that case as well if you are planning on fitting the cowling. You may be able to call some of the large engine shops and see if they will sell you a scrap case, crank, sump and cylinders. You could clean up all of this junk, give it "spray can overhaul" and bolt it together then use it to fit the cowl, baffling, run engine control cables, FWF wiring.....