I used a g 26 for my engine. what I did was stand the pane on its tail and placed the engine on the firewall. I then slid on the cowl and centered it with the center back plate onto the cowl. Of course I had to take the jug off the engine to be able to slide the cowl over it. worked like a charm. I was also able to get the exact dimensions of what I had to cut off the cowl having the engine already mounted and able to slide the cowl over it. I didnt get any of those air restrictors. I used a wheel axle collar.