Paul, I have had some time to get back to my CAD education with Alibre.
I'm working out the cowl profiles, and was wondering if you had some simplified models of the 13b in combination with the RD-1c and Doddridge plate. I was hoping to kinda stick them in to make sure everything clears. I'm using the extended mount dimensions for the lightweight version of the 13b on the Zenith CH-640.
C. Smith

Try some of these.

Paul Lamar