LeeA:
When installing a factory power brake booster, you must drill one hole and it's location is dimpled on the firewall. I have converted several of my '64-'66 Chevy trucks to power brakes using the factory power brake booster and mounting wedge. I am not sure what drilling or modifications are required when utilizing a custom power brake booster.
In either case, there is some drilling of the firewall required. Good luck with your project.
Tony
