[locomotivebreath]

Just some thoughts on the quick performance 9 differential that I installed in my 68 GTO . It’s a really nice unit and great place to deal with. It shipped in 3 separate boxes - housing, center section and axles . I reused my stock drum brakes . You will almost certainly need a longer drive shaft - about 1.5” in my case and if you’ll want adjustable upper control arms as your pinion angle most likely change . Mine started out about 4.5 degrees down . I measured my drive line angles with a digital finder and confirmed things with the tremec app to dial it in . I followed their break in procedure and today put about 120 miles on it and the diff is dead quiet . I went with a 3.50 gear down from the 3.90 I had in the bop and it was a good choice. I really didn’t notice any loss of performance and feel like I have more use of the engines power band and use of each gear . I also installed a QA1 I” bar that goes around the back of the housing and it made a noticeable difference in oversteer from the 7/8 bar . It’s an economical swap but keep in mind the added coin for control arms and drive shaft .

[OCMDGTO]

X2 on QP, great price, quality, and customer service. My stock driveshaft fit and I ran it until I did an engine upgrade. I'm assuming you already had boxed lower control arms? My pinion angle was good and I'm still running stock upper arms. Can you post a Pic of the sway bar?

[Formulajones]

I've installed them in others cars and currently have 2 of them in our personal cars. They fit and perform as expected. Pinion angles good right out of the box. I've never had any issues with them.

[joes455]

Do they center the pinion with the center of the driveshaft tunnel?I know the stock rear in the f bodies are always offset.

[jerry455]

We are going to find out. I bought a Moser 9" for my 1976 Firebird, going to install it this weekend. They had a great deal on the kit this past winter, about a third off. By the time I would have updated my 8 1/2" 10 bolt, it would have cost a similar amount. I looked into C Clip eliminators and all the companies who sold them did not recommend them for street or auto cross use. Once it is in, I will have to get a driveshaft made. Upgrading to 1350 u joints. Going to use the 11" rear drum brakes I already have on my Firebird.

[Skip Fix]

Strange does, or did, make a C clip eliminator for stock diameter axles that uses the 3.150 taper bearings as their "Street" C clip kit vs roller bearing kits.

Probably going to use a QP 9" in the 64 Impala project. Thinking Explorer brakes. The GM pattern ends for 3.150 make the backing plate bolts really tight