A-body Disc brakes

Now that is an informative website! Wow, almost to much information for me.

I had asked what size bolt pattern, and he told me that they were 4.5, so it seems maybe they have been upgraded to the larger bolt pattern and also he said that these are single piston calipers???? Seems like a pretty good deal, and I am leaning towards buying them.

Any more input would be appreciated.

John