Jim,
A-Body wise, the nodular iron 10 bolt housings were used, for sure, in '68, 69, & '70 Pontiac A-body hsgs when car was equipped with 3.90 or 4.33 gearing. I would also bet in the very few 3.90 factory geared '69 GP's. The nodular hsng may have been used in some specially ordered '67 A-body rearends as well...just have not seen one yet
The nodular hsg carries a cast N on the front side of the center housing & each year nodular center hsg will have a different casting number than same year gray iron hsg. Trying to put together a log of all of these numbers & location of the "N"s.
In Firebird 8.2 Pontiac r/e's, a nodular hsg was used in the factory 3.90 rearends in '68 & 69, & def in the '69 3.55 HD Safe-T-Tracks rearends in RAIII T/A's & Birds equipped with HD Safe-T-Track. Not sure about '67's, but would not surprise me if there was a twin traction bar nodular case r/e for HD Safe-T-Track '67 Birds.