70 C10 drum to disk conversion

[tobascofred]

I have purchased a SSBC A126-71 front drum to disk brake conversion kit for my 70 C10. I have two questions -

1) While the list of required tools does not mention needing a drill, in the instructions they state that a new 3/8 inch hole must be drilled in the brake pedal one inch below the existing hole - does anyone know why this is needed / if it is really required?

2) When I removed the old vacuum booster, there was a rectangle of ancient insulation matting between the bracket and the firewall - it is trashed. I assume that it is supposed to make a "seal" to keep engine bay fumes out of the cab. Has anyone ever used some other sort of a "seal"?