['ol Pinion head]

From looking at the pics, the rear is a Pontiac 8.2 10 bolt. The shape of the lower webbing of the center housing is the telltale. I can tell the posi carrier is an original carrier. If this rear has 3.23 gears & a N housing, I would ck the dates inscribed on the gears & the factory code stamping on the housing tube. Either one of two things is possible, a set of 3.23 gears have at some time been set up in an original '72 3.55 STT coded rear's original housing. This would require installing a mid ratio 8.2 STT carrier. Either that situation, or 3.23's were factory installed in one of the remaining '70-72 Pontiac 8.2 cast Nodular housings. Have never seen or heard of that before, but with axle production winding down of the '72 style 8.2 Pontiac rears (73's would take a totally different geometry 8.5 A-body rear) there remains a possibility that Pontiac's axle plant built such a deal just to use up an excess N housing. Would be interested in pics of the stamped axle tube among other pertinent pics. Can relay '72 coded N 8.2 Pontiac rears are few & far between.