Lots of good info here. Thanks everyone. I'm at the point of installing the engine, a Thunder Tiger Pro 46. The instructions say, "the distance from the firewall to the front of the engine thrust washer should be 100mm." Does this sound right? In test fitting, this seems very tight to the firewall. Is the CG balance right with this measurement?

I've also read of references to the pre-installed engine mount as not being centered, and so the mount needs to be moved 3/8ths to 1/4 inch to have correct engine alignment. Is this right?

Looking for any advice on these issues.

Thanks, Jim