I will probably just leave the firewall as is since it sounds like it is already fuelproofed. However, I have two small holes in my firewall because my buddy and I redrilled the hole for the throttle pushrod. We didn't like the pushrod's angle to the engine (the pushrod brushed up against the engine when I advanced to full throttle). I may fill the hole with epoxy 30 just to seal it. I can't think of anything better to seal the two small holes with.

Thanks!
Bjfrankl