Rusty - I am going to have to extend my cowl something like 4".  I was thinking about adding a flange to the firewall rather than the cowling, since I trust my AL work way more than my fiberglass.  Perhaps you could do something similar.
Kevin Lane (thinking outside the, uhmmm, cowling, although your cowlings sometimes look more like, well, never mind!))
e-mail-> n3773@comcast.net