How? You will need a totally different custom rear. NO 3.90 are available for that rear. NO aftermarket gears are available for that rear. No aftermarket posi units are available for that rear. And lets call it what it is.. 9.3 Oldsmobile full size car rear. ALL 455 factory cars received this rear from 1971 - 1976 Buick Olds and Pontiac. IF you have a FULL SIZE GM car...IT is VERY difficult to get any performance gear over 3.42... and even 3.42 and 3.23 are a tuff get. NOT saying it is IMPOSSIBLE...It is just very low probability. Do not stop looking for the 3.42 and 3.23 But no need to do the 3.90 or 3.73 there just is not one to get. Now the Pontiac 1965-1970 they had performance race gears as the catalina was the race car in its day... they had 3.90 4.33 etc. I personally had a few sets of the 4.33 gears with the 10 bolt cover and 12 bolt guts. (reference picture) Jim J D
Am I reading this right? There are no parts available at all for the 3.07 posi unit used in 1966? I have an Electra with that rear end in it, and it needs an overhaul. It's going to need clutch packs and bearings at the very least. I think the gears might still be OK, but who knows, when they opened it up the last time they said that the clutches are just about done and the bearings are getting slack. This probably accounts for a vibration I have going at 70 mph or higher. So if this rear end is a one-year wonder, is there anything I can bolt into it's place? (ie remove the whole thing and replace it)
I can get you the clutches and the bearings...JUST no gears and if you are going steeper on the gearing IF you can find them you will need a different POSI unit all together ...GM has series carriers... 2 3 4 etc. which fit the different ratios. 2.40 to 2.56 etc. and 2.73 - 3.08 and 3.23 -3.42 like that... It is not we can not rebuild what you have we just can not go to the performance shops and just pull a NEW posi and gears off a shelf ...IT does not exist. You can not get spider gears either... That is a GM item .... Might be able to whip up some custom stuff from another unit as long as we have something felt to compares and machine measure. clutches NEW 149.00 Bearing kit all bearings and seals for the center (excluding axle bearings and seals) 145.00 Plus the ride.... Jim J D RAce
I have 4 NEW GM spider gears. I paid $175.00 ea. + shipping for them yrs. ago. I'm keeping them for my rears. The place I bought them from had 2 left, but that was yrs. ago I'm sure they are gone by now. I have a one yr. only Posi carrier that I bought NEW back in the 60's. At the time with my shop discount it cost around $400.00 which I would sell. Part # on box 1271627 Group # 5.510 Casting # 755 For 3.36 ratios & up. Tom T.
Ok, thanks for clearing that up guys, I was getting scared there for a minute. I'll try and find out just what series/age/type mine is before I contact either of you for parts, because I'm not likely to get them here in Canada.
If you are unsure what you have Try Alberta driveline on the yellowhead highway. The guys there were helpful
Are they the outfit just before 97th Street? They were the ones who told me my rear axle is pretty much shot, and they did 4 of my u-joints. This would be about 7 years ago, are they still any good?
An update on my plan to get a posi for my 66 Wildcat project. Firstly, thanks to everyone that helped with their knowledge, your info was very valuable and steered me in the right direction. I have found and ordered from Gevo Gears and Rears in NY a Buick 9 3/8 '66 specific posi carrier that is the same series as my current carrier. I will receive it in about two weeks then will share some photos. Marco
Same place. They rebuilt and balanced my driveshaft and pressed on bearings for my axles. They were helpful and reasonably priced. I was going to have them source a posi carrier for me but I lucked out and got one from Cole (Kamloops). His buddy did the work for me.
I received the 66 posi I ordered for my 66 rear end. Here is a photo of the new posi on the left and my original open carrier on the right. You can see that the two are the same series so I can just move the ring gear to the posi. Next step is to get new bearings, clean and rebuild the rear end. I'm also busy with a disc brake conversion on it.
Must be the last new one on earth? I took me like 7-8 years to get my 3.42:1 '66 Posi setup sorted out, with the carrier/gears coming from one car and the housing from another, since I couldn't fit the stuff in the housing on my car. A real PITA.
MarcoD,I just now noticed your post...but anyways I do currently have the totally "Correct" in mint condition and ultra hard to find 1966 Buick Full Size 9 3/8" Posi Unit that you were in search of. As monzaz (Jim) JD Race stated the "Correct" casting number is ED-32103-D which is exactly what I have so if anyone else is in need of one of these feel free to contact me to further discuss.
Thanks Dif_Dr, the one I bought has got a different casting number but Jim confirmed that it is also correct for my rear end. I haven't installed it yet as I have been doing some suspension and engine mount work.
Having spider gears issues with my 66 Wildcat Coupe. After reading this thread and opened the rear end I have found the following: -307 open rear end - Carrier bearings are both same size, understand to be early design? - Gears and pinion looks to be in good shape - BUT my side gears and spider (fitted on the bolt) has considerable slack., specially the spiders on the bolt So can you guys confirm that there is absolutely NO aftermarket spider/side gears to find? Or NOS? Or where can I find any spider parts for the 93/8 Wildcat rear end? Sitting in Europe so do not know the US market to well. Any help appreciated Thank you
I will check the shelf and see if I have any open diff carriers...DOUBTful but I will give another look see.
Sounds great Jim. Appreciate the effort. If no success. Any pointers towards a salvage yard or someone who can machine/make new ones would be grateful.