[Authentic-242]

I have a 67 model year (Dec 66) Safe-T-Track 3:23 rear (cone posi worn out) in my 71 GTO. It has the 3-hole flange axles in it which I understand are forged vs. the 1-hole versions which are cast. I recently put new Timken sealed bearings on them after one of the bearings grenaded. I also have a 72 model year (Sep 71) Open Diff 3:23 rear I purchased a while ago that I planned to rebuild with a new cone posi unit for street use/street tires only and put into the car as a replacement as I believe the 70 up roller bearing design handles loading better than the older sealed ball bearing design. I see the axle flanges in the 72 rear have 1-hole, so I assume in 72 this was a standard cast axle. The only higher numerical gear ratio offered in 72 A-body 10-bolts was 3.55. In 71, 4-pinion case 3.90 & 4.33 was also offered so I assume they are heavy duty and forged. So I have 3-questions 1) are my 72 1-hole axles cast and 2) are the 71 4-pinion case axles forged and is the bearing design between 71 -72 the same allowing them to be used for a 72 rear and 3) would I be better off to just put a new cone posi in the 67 and ignore the advantages of a better bearing design for a street driven weekend toy. I know I can buy aftermarket forged axles, but I'd like to get these answers first. Tx