Well, I cant help with any info on aftermarket kits but I would look for a 4 door 67-68 c body for parts and grab the brake pedal assembly with all the hardware. then buy reman booster w/master from RockAuto.

You can buy it for drum or disk brake applications,

Exceptional Architectural, Yacht and Automotive scale models. e-mail modelmakerinc@att.net for a portfolio review. www.modelmakerinc.com