Search the VMF archives... 65Fastback6 and I had this exact conversation last week.
Apparently, the '64 thru '66 I6 Convertible came with both type rear brakes... The larger 9x2 1/4, and the regular (as other stang models), thinner 9x1 1/2. Take a picture of your rear brake drum, and we can easily tell you which ones you have, There is also another way though. If your rear drums are the same size as your fronts, Then you have the larger 9 x 2 1/4, and it takes the same drums and brake shoes as the front drums.
If the rear brakes and brake drums are thinner than the front, Then you have the 9x1 1/2 that is also on the I6 Coupe and I6 Fastback. My original '66 Convertible has the thinner 9x1 1/2 brakes which uses the 7048 Hardware combi-kit as you inquired about...so if you have the larger brakes in the rear which match the same size as your fronts, You would need the same drums as the front and the same 7047 Hardware combi-kit as the front.
As for the distribution block, I'm sorry, but You have the wrong one. You need the classis "H" distribution block that is used in the 1967 thru 1970 Manual drum brake cars. This distribution block has an internal pressure valve so that if you lose the front brakes, you will still have the rears and vice versa.. You only need a separate residual pressure valve if you have disc brakes in the front...so you don't need that here.. If you can't find the valve from a junker or on Ebay, NPD still sells them for $69 bucks last time I checked, but it is mis-labeled in the NPD catalog, so go by the picture, not what it says in the caption. You will also have to buy the small light switch as well, or you can just block it off with a brass fitting where the switch usually screws in. You will also need to bend and re-plumb your front brake lines. The original rear brake lines CAN be left in place if it is in good shape, but I would replace the rear line if it needs replacing, or simply replace it at a later date.
The port and chamber closest to the firewall is the front brakes on Fords. (Chevrolet is reversed, which causes alot of confusion!!)..
If your Front drums are original, You will know it...Because you WILL NOT be able to pry them off. You will need to have them pressed off by a reputable local machine shop. If they are re-usable, Enlarge the lug holes in the drums and Re-use them. Otherwise, You will have to replace the studs in the Front hubs OR, You will have to enlarge the holes on the new drums on a drill press about two or three sizes bigger to accept the original "staked" studs...Otherwise, It will not fit flush. I chose the later, and enlarged the holes on my drill press on my new Front drums...so they could clear the original "staked" studs.. Otherwise, You will have to change the studs, the front hubs, or both.. If you do it right, It will work out perfectly. This is a well known problem.. Ford originally "staked" the studs to the hubs...IT IS ABSOLUTELY NOT NECESSARY to get them re-staked.. You can leave the new ones unstaked and the drums/hubs will be fine...It also allows you to take off the drum fast without taking out/off the hub when doing a normal brake shoe/brake job change. If you are really Super Safety conscious, You can use a stud safety "C" clip on one or two studs to secure the drum and allow for future easy removal.
Let us know what size rear brakes you have. 65Fastback6 and I are curious.
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