Attempting to remove and replace the power brake unit on a 1981 automatic. GM shop manual simply says remove nuts from 4 studs on firewall. Yeah, right. How do you get to them? I can see them and if I wiggle my fingers just right, I can touch them. I know they're 14mm but can't get to them with either a standard or deepwell socket with any configuration of extensions or U joints. I've removed the Tach/Speedo to do some other work and thought there might be some route through from there. Any help would be appreciated.
Gary '64 327/365hp '78 L82 '81 350