Al,
If you want to add some epoxy in missing areas around the firewall, have at it. Most Lancairs' need tailweight to balance, so adding any weight up front is probably not a good idea. I altered the guts on our latest Lancair (see photo gallery) to move most of the equipment back into the baggage area. You can see pics of the alteration here
http://www.rcuniverse.com/forum/m_80...ictures/tm.htm
At any rate, once the engine mount is...well...mounted, It can't possibly pull out of the plane, which, on a typical wood-constructed arf could have the engine/firewall leave the plane.
I am sure that the firewall is glued to the inside of the fiberglass firewall as I removed the one from our first Lancair (crashed [] ) to use as a drilling template on the new one.
There's glue all over the front face of the ply firewall, not just on the edges.
Didn't mean to accuse you of dislexia in particular, I've seen this topic come up before and it always caused me to wonder.

Paul