Belltech Disc Conversion Spindle Issue

[R.S.S.]

I'm currently working on installing a Belltech 952SP (4/5) kit on a 69 gmc. I'm having some issues in regards to the upper ball joints. I've search the forum and contacted Belltech and still haven't had my question answered.

The kit comes with spindle part #3121 which requires me to upgrade to 71-72 brakes which is no issue. However when I go to bolt the spindle on the upper ball joint it will not seat as the outer diameter is to small. The top of the spindle just binds on the control arm. Considering these are conversion spindles I would have expected these to bolt directly onto the standard 69 ball joints. This does not seam to be the case.

Dose anyone know what the OD measurements are at the top and bottom of the tapper for a 71-72 upper ball joint as well as 73-87? The spindle has the following measurements for the upper ball joint:
Large opening: 0.710"
Small opening: 0.531"

Thanks