Looking for manual drum/drum to power dual master cylinder drum/drum conversion kits for '66 Mustang coupe, auto trans, and all I'm finding is disc/drum or disc/disc setups. Any recommendations on specific kits or places to check for this?
in other words you want to upgrade the stock single master cylinder to a dual bowl master cylinder. there is no kit for this as such, but the conversion is easy enough. if you have power brakes already, then get a drum/drum power brakes master cylinder from a 67 mustang, and plumb it in. you might have to clearance the shock tower for it to fit properly.
if you dont have power brakes and want to add them, then there are conversion plans and parts available from many places, and you have many choices. for instance mustang steve uses and geo metro(?) brake booster. npd sells stock boosters. either way you are going to have to relocate the pin on the pedal that allows you to actuate the master cylinder, and mustang steve has the necessary parts and plans to do that as well.
I would read as much as you can on this...most people are not happy with the result after converting to power brakes on the early mustangs, there are issues with a lot of conversions out there. I have long since given up any such plans myself since power brakes dont help a vintage mustang stop any better, they just reduce pedal effort required, not to mention that if your engine has low vacuum(big cam, individual carbs, etc) there may not be enough vacuum to properly operate the booster anyway. Power brakes have about as good of reviews as rack and pinion conversions...lukewarm at best...some people have success, most people are less than thrilled with the issues that crop up. If you actually want the car to stop better...you are far better off upgrading the brakes with a kit like those sold by Street or Track(Shaun appeared in an article not too long ago and cut off something like 30ft from the 60-0 distance over factory).
wicked is right, pedal effort on an early mustang, or falcon, with manual brakes isnt that high to begin with, so in reality there is no real need for power brakes.
Thanks for the replys guys. The reason for adding power assist to the brakes is that the car is going to be mostly driven by my wife, who has expressed an interest in having the brakes "feel" like her more modern daily-driver. The dual pot master is for safety's sake.