I almost did the master cylinder upgrade a month or so ago. I have the adapter and a Tahoe to steal it from. I was replacing the vacume booster after it failed so I had a good opportunity. This is something I have wanted to do for a long time.
I really wanted some damn good advice as to why not to do it. I was researching the rpo codes for my burb, i realized that my brakes were one of the best available on the 1500's and i just didnt think i had the engineering understanding to actually mess with it properly. Remember, gm put these trucks in a wind tunnel and actually made them aerodynamic.... that front valance ect.... they had the best engineers build these trucks, I just couldn't believe they would put ****** brakes on them and something else must be happening.... 20 year old system that needs to be rebuilt properly was my thinking. I didnt think I had a problem whatsoever with my master cylinder and couldn't bring myself to mess with it. My brakes worked absolutely fine before the vacume booster blew. I wanted some understanding as to why some people swear by the upgrade and some people change it back to the original. Well I reached out to Shurkey and his explanation lined right up with my thinking soooooo I didnt swap it.
I still have the adapter in the glove box.
Al