I posted a message in the main forum a while ago looking for a master cyl. push rod boot for my Mav (4-wheel drum brakes). I still have not been able to track one down, however there is one on the John's Mustang online catalog, for 65-73 Mustangs, that looks just like mine. http://www.johnsmustang.com/Catalog/2266/ My question is that the inside diameter they've given for this boot (1 5/8") is different from the boot I've pulled (1 3/8"). Does anyone know if these parts are interchangeable? Is it possible I'm taking the measurements from the wrong place? And has anyone here dealt with John's Mustang to know how good they are about dealing with returns, etc. I'd really like to get the master cyl. back in so I can get my Mav back on the road. Thanks for any and all help.