Is this the one you're talking about?
http://www.doriantool.com/2005_MTA_C..._2005_P-18.pdf

Actually, it looks like the MDN15 is a better fit for the Myford's
.64" center height, although the Myford's extended bolt and nut would
interfere with the swing of the locking lever. I'd like to keep these
parts so I can easily switch back to the original clamping arrangement
if necessary. I guess the MND20 might be the way to go, if there's
room to enlarge the mounting bolt hole, and I'd have keep another
wrench in the tray to remove the toolholders :-)

I have the MDN20 and it works well on the myford super 7.
The center height is fine for normal tool holders. I did
have to grind a little bit off the boring bar and parting
toolholders to get them low enough. I used a belt sander
followed by surface grinder to make them look pretty.
Forget machining them; They are extremely hard.

Myford uses a 7/16 post and the MDN20 has a 3/8 hole.
I replaced the myford 7/16 post with a shopbuilt 3/8.
Just press the old one out of the top slide and install
the new one. Initially I wanted the ability to switch between
toolposts too, and the 3/8 bolt prevents that but frankly once
you use the Qc toolholder you will never use the myford 4 way turret.
I believe you could enlarge the center hole on the MDN20 toolpost
with an EDM. I doubt you can drill it.