Need to drill and tap my 400 sb for the clutch pivot ball. There are two undrilled/untapped bosses on the side of this engine. One is above the oil filter and the other is in front of this location by 3-5 inches. Which is the proper location for a small block in a '69 chassis?

See the reply to your post in the Engine & Drivetrain section.

A picture is worth a ....

Since I've got the clutch out today, maybe a picture of the back of my 67 w/327 might help?
http://www.surfari.net/~scottmoo/327nclut.jpg
See that shinny lever shaft a few inches above the filter and about an inch to the left. That be it.
The pivot looks to be indented about 1 1/4" from the back of the block.
Regards