We cut all the bumps from the firewall then made a cardboard template. That was then turned into a single sheet of steel to cover the entire firewall.
That steel was bonded to the old firewall using FUSOR then welded around the edges and ground down.
Fiberglass would be a bad idea.
Pics:
http://www.bestofshowcoachworks.com/...maro02_12.html
__________________
"A ship in port is safe, but that's not what ships are built for."
See Bad Penny run the cones:
https://www.youtube.com/watch?v=8GUPPIX-92U
1971 Chevelle Wagon - Roadster Shop Chassis ProCharged Shafiroff LS and lots of yada yada
1968 Camaro - Project Track Rat - 440 RHS LS