Disc Brakes question
thanks for your information, the kit I have is
SSBC A153-1 SSBC USA Drum to Disc Brake Conversion Kits , my mechanic called SSBC and they told him that they are designed for 10 inch front brakes spindles
Based on the application list and the advertised year range for the kit it appears you need 10" drum spindles for a 67-72 A-body. That is important because there are 2 different versions of the 10" drum spindle, either 67-72 or 73+. For your car the 67-72 spindles don't require any changes at the upper ball joint or UCA, and just an increase in the bolt diameter for the lower ball joints compared to the 9" drum spindles. The 73+ 10" drum spindles use the later larger upper ball joints, so you'd either need a UCA swap to 73+ UCA's and upper ball joints or a set of ball joint taper adaptors. They also use a different wheel bearing, so, it makes a difference for the kit, the early and late 10" drum spindles would not be interchangeable for the kit either.
So, based on what I see you shouldn't need to do anything with the upper ball joints or UCA's. You will need to either drill your lower ball joints for the larger diameter bolts or buy new ones, and source the larger bolts. And you will need to find a set of 67-72 10" drum spindles. They're not reproduced, so, you will need to find a good used set.
I would agree that the SSBC kit was probably not the best choice because you have a source a used set of spindles for it. As opposed to using a kit that's based on the 73+ disk spindles, because they're reproduced and readily available and use an improved larger wheel bearing. But those would require ball joint adaptors or new UCA's, so, there's always a trade off.
