Thank you MinnFlyer, DaRock, and ChuckW...

I actually have seen the firewall pictures DaRock posted in the Skybolt build thread, and thought a "made for OS" engine mount would distribute the compression and releve stress on the firewall ( well presented by DaRock in the skybolt thread). I now agree that beefing-up the firewall is the way to go. How thick should the Airply be? Won't adding thickness to the firewall make the engine stick out of the cowl a little farther?

AND the adjustable mount was UGLY.

ChuckW, thank you.