On the topic of converting to disc brakes 61 pickup

[mchacon]

So I've read some of the discussions and looked at pics but can anyone tell me if I can avoid having to go the whole cross-member swap or pay for a very expensive kit in converting my 61 short-bed stepside to a disc brake setup. So I have the disc break and spindles of a 73 but the 73 ball joints I purchased don't fit on the A-arms. the screws that hold down the upper ball joint housing don't match up with the holes in the 61 A-arm. ANy suggestions?