You should be able to get a frame repair section from GM. Cut out the damaged section & weld in the new section. They have instructions on how to do this.

The best carbides are from Buckeye Carbide. http://www.buckeyecarbide.com/ Any shape, any tooth count, any length. I've been using them for years doing cylinder heads & I never seen any others that would keep the edge for so long. Keep them lubed up so the aluminum doesn't stick & they will ...