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Hi I’m trying to get a hold of monzaz as he seems to be the most knowledgeable person when it comes to these things, I have what I believe to be a 8.875 pontiac from my research here, it is out of a 74 olds delta 88 has the 8.2 olds 10 bolt cover with a 12 bolt ring gear 30 spline pinion and I got these numbers off of it
Axel tube code: UA P 115N4
pumpkin code: 480362
From what I’ve read all those seem to match up with what I have, I have it in a demolition derby car and do not need to go long distance and was wonder what I needed to do to do 4.10/4.11 or whatever the closest thing is while keeping it 30 spline, if I even can… thank you for your time
kabe
I tried that earlier and just now again but it’s saying I don’t have valid permissions?
I will try on his page, didn’t realize he had one. Thank you
kabe
8.875 is a Pontiac. Cover is NOT 8.2 BOP they are totally different size.
There are NO gears for this rear.
Fabrcraft Metalworks had produced 3.55 for a few years and then now they are missing action.... Along with the BUICK 8.25 GS gear sets and even the 9.3 Pontiac gears are slim pick'ins.
I do not know what is happening over there with there business...I have tried to buy gear sets and they will not sell either. ?? They say they only have enough for them selves...lol. Well I do not know how that is all going t work staying in business.??
1971 - 1976 : 8.875 Pontiac full size car rears will have 30 spline pinion and 31 spline axle shafts... In 1971 - 1976 I believe GM cut down the ratios from 2.29 - 3.42 max.
BUT in 1965 - 1970 era this rear was used by Pontiac as a race car rear and they had VERY steep gear sets from gm over the counter performance division.
I personally had 2 sets of 4.44 ratio gears
The 1965 -1970 Pontiac rears were installed in the lower powered OLDSmobiles too. The pinion splines were 28 spline in this era.
NOW you can swap the gear sets from era to era...BUT ytou will also need the yoke to mate the drive shaft.
IN 1971 -1976 era the yokes were round 4 bolt flange flat and had a drive shaft with the cardin joint set-up. ...cut down on driveline vibes.
I hope some of this info helps. WISH I had gears to get you....JUST do not....ALWAYS looking too.
Final :
1971 - 1976 era FULL SIZE cars you will need to hunt for. anything with a 400 350 4bbl carb will likely have this rear. 455 car received the BIG OLDS 12 bolt full size car rear.
NOW another thing too is ALL 1971 - 1976 car rear FULL SIZE will interchange complete total drum to drum rears with out any mods. That might be an option if you find one with 3.42 ratio. IF YOU ARE stuck on the 4.10 deal GM 10 bolt 8.5 will have to do as it is the only rear you can by parts for at this time in the aftermarket.
1971 - 1976 era ALL low powered full size cars with 350 2bbl and 350 or 305 chevy motors likely got this 8.5 10 bolt cover rear.
JIM
J D RACE
That’s a real bummer that there is nothing out there, I’ll have to take a picture or my reared to share. In the derby world everyone uses the 4 bolt flange for everything transmission and pinion side, usually paired with pinion brake instead of running the front and rear brakes, I’m not very knowledgeable when it comes to rear ends so I pulled that rearend thinking it was just a 10 bolt and ordered my stuff for a 10 bolt,(why I wanted to keep the 30 spline pinion) do you know if any other rear ends share the 28 spline as the places that sell demo derby parts don’t offer a GM 28 spline pinion yoke, I know the ford 9 inch is 28 spline but don’t know if it would work or not, I would really like to keep the rearend I’m currently using for those set of rules as I have a 14 bolt for the higher rules. If the ford 28 spline does work would I have to swap over carrier and everything or would just a ring and pinion set work? If push comes to shove I’ll just build my 9 inch, was hoping to save it but it’s just the way she goes. Thank you a ton Jim in my short time here I’ve noticed you are doing great things for this community, this is my first forum I’ve ever joined and was just to speak to you.
