I am wondering if anyone has dealt with this similiar situation. I am mounting the FF-320 Four Cylinder to the Great Planes Pitts. By using the mount that comes with the engine, and then mounting the engine to this mount, the prop backplate protrudes 5/8" too far forward, the exact depth of the rear mount. I am considering mounting the engine directly to the firewall, and instead of hanging off the mount, it would hang off the firewall. Same bolts, etc. Is anyone familiar with this? Would this work?
I can't see the difference whether the engine is bolted to the mount, or whether it is bolted to the firewall. The only difference that I can tell, is that the coverage area would be a little greater on the mount vs, the engine. Any input would be appreciated.

That should work just fine. I mounted a 60 size 2c by the backplate screws through the firewall one time and it worked great. Good luck.