I bought a posi axle a while ago, and been waiting for the motivation to change it to my 67 rivi. The time is here. Im driving quite long distances, and i discovered that the posi i bought is a 3,07, not the 3,42, which is great! Are these 3,07 posi diffs rare, or have i been just avoiding them.... Table is warped....
Both those gear sets are super RARE hard to find especially the 3.42 set. The "big car" 9 3/8 rear end has zero aftermarket support for gears so we're forced to find good used originals. The stock Rivs usually came with the 3.07's and the Riv GS's had the 3.42's.
I see a few more 3.07's but IMHO both rare. Good to see you here Jukka, if you need anything let me know! Ted
I didn't even know the 9-3/8" posi came in the 3.07 ratio...3.42 is the only one I thought was available in the GS option.
Posi is just an option... Like anything when your building a car you can check off anything ...unless they had power restrictions like big block with radical race cam and a/c option etc. Most Penn state cars were posi because of the snow and mountains... so that was always a good place to find posi units back in the day.
My '70 Riv came stock with a non posi 2.78 rear end. I have had luck finding many 3.07 Riv diffs with and without posi. I swapped my diff for a 3.07 posi and this was one of the best upgrades I've done. Now if I can only find a 3.42 to replace the 3.07 I'll be in business.
I might be able to help you make that possible, I don't want to clutter this thread so PM me if you'd like.
I don't think the 9 3/8 carriers need anything special to add the basic clutches making them a posi. Dunno, could be wrong. But going from 3.07 to 3.42 makes a world of difference in city driving.
Open carrier and Limited slip (posi) carrier are 2 different things. Nothing interchanges in them. Just so that is clear. You can not just add clutches to an open carrier and voila... you have a posi ! Jim JD Race
If you the OP will permit a slight off topic Q, what is different on the 9 3/8"s to provision for clutches?. I guess I could look at mine, but not interested in getting messy right now.
I'd rather a 3.23 if one can be found. The one in my parts wagon had been changed, the 3.23 was replaced with a standard 2.78. Phooie!
English isnt my first language, so i dont quite get the word ”provision”, but as seen in the pics, the carriers (?) are totally different, thers no way to get the posi things inserted to an open carrier.