Mocking Up Firewall for Master Cylinder Studs

Just a suggestion, but why not section a part of a firewall from a junkyard car, with studs and holes all drilled? It'd be a matter of laying it in where it fits the existing curves, cutting, welding, and done?

Surely someone on here knows of a car going to the scrapper, or has a hulk with a little-needed piece like that.