On the plan I measured 4-5/8" from the firewall to the back side of the spinner backplate. I don't think I can hold that dimension with the Saito engine. If Imeasured my Saito .82 correctly, the distance from the back of the prop hub to the back of the bolts on the carb is right at 4-5/8". Add 3/8" for the thickness of the Hayes motor mount in back (carb assembly will hit), and 5/16" for the Saito prop hub, and Icome up with a dimension of about 5-5/16" out from the firewall. Does that seem correct? Can I ignore the 5/16" thickness of the prop hub? That would bring it back to right at 5" from the firewall to the back of the spinner. The Saito would stick out 3/8" farther than the motor on the plan.

Joe