As you can probably tell from this thread. I haven't been getting as many responses as I used to get here. Maybe I didn't post in a good spot, or use a good title.

I tried the RCgroup Forums too. I got a suggestion from one of their members. https://www.rcgroups.com/forums/show...&postcount=125 I contacted that company (Fiber Glass Specialties Inc) that makes cowlings for some airplanes. It sounds like their cowling is close to what I have. Looks if I ground it down, it might work.

Here is the measurements the company gave me.
Fiberglass Specialties

DP-7 for the Pica 1/5 Waco measures approximately 8 1/8” inside diameter by 5 ¾” deep.