alternate 3rd members

[DrRansom442]

8.5's bring the money they do because they save the expense of making something else work. Convienience costs money. Plain and simple. Sure, you can find a 12 bolt out of some car, and then spend spend spend to make it fit...

4x4's are easier candidates for creativity because a leaf spring axle is a much simpler swap.

'94-'96 Impala SS's and Caprice 9C1's have an 8.5" rear.
Rear disc brakes too.
But they are also a 5x5 bolt pattern, so you'd either need to change axles, redrill your axles, or swap to a 5x5 wheel. Not to mention that it's too wide to begin with.... See why the 8.5 looks better and better?

If I was putting up the coin for a new rear end, I'd get a complete G-body 12-bolt from Moser and call it a day.

9C1s are all over junkyards, I wouldn't mind switching to a 5"x5" ... I can just use the front rotors (be another Cutlass upgrade) ... what I was more concerned with is "how well does it fit?". Width is an issue - yes and I will have to make some measurements on the car. If aftermarket wheels are in order .... some of the width I can make up with backspacing.

With the price of used up 8.5" rears - a 12 bolt from Moser does seem to have it's appeal, but it's beyond my budget right about now.

 

[78MC-BBC]

wow hear i was thinking that when i paid $600 for a low mile 8.5 posi GN rear end with drive shaft was expensive. i have noticed the rears going around $800 for a non posi and $1000 for a posi rear plus you still would need the driveshaft

 

[DrRansom442]

wow hear i was thinking that when i paid $600 for a low mile 8.5 posi GN rear end with drive shaft was expensive. i have noticed the rears going around $800 for a non posi and $1000 for a posi rear plus you still would need the driveshaft

Yeah and for just a bit over that grand, you can get a new open 12 bolt rearend - seems crazy to me ... even if it was twice the price - new seems to be a bargain compared to a differential that probably needs to be refreshed. I'd be happy if I could find a deal like you got 78MC-BBC.

 

[joe_padavano]

So these don't work? or am I missing something?

The original question was about "cheap" and "bolt in". Aftermarket control arms to correct the misalignment of the upper control arms aren't cheap. Custom offset rear wheels to correct for the wider axle are neither cheap nor bolt-in. And frankly, A-body axles of any type are rapidly becoming expensive.

As for welding onto an S-10 axle, how do you plan to attach the tabs for the upper control arms that are cast into the center section normally?

 

[DrRansom442]

So these don't work? or am I missing something?

The original question was about "cheap" and "bolt in". Aftermarket control arms to correct the misalignment of the upper control arms aren't cheap. Custom offset rear wheels to correct for the wider axle are neither cheap nor bolt-in. And frankly, A-body axles of any type are rapidly becoming expensive.

As for welding onto an S-10 axle, how do you plan to attach the tabs for the upper control arms that are cast into the center section normally?

A-body and B-body rears are still consideribly cheaper around these parts than a G-body 8.5" ... not to mention a 12 bolt would be yet another improvement. If I can spend $300. on a differential and $200. on new control arms ... that is still cheaper than a $1000. rearend right? Wheels are bolt-on no matter what the offset, but only needed if I upgraded to a 5"x5" offset to use B-body parts. I am not trying to be arguementive mind you, but if this IS viable ...
I don't have tons of money ... in fact I am going to have to limp along on the highway gearred factory 7.5" for awhile. The engine/transmission swap is already taxing my bank account.

 

[joe_padavano]

A-body and B-body rears are still consideribly cheaper around these parts than a G-body 8.5" ... not to mention a 12 bolt would be yet another improvement. If I can spend $300. on a differential and $200. on new control arms ... that is still cheaper than a $1000. rearend right? Wheels are bolt-on no matter what the offset, but only needed if I upgraded to a 5"x5" offset to use B-body parts. I am not trying to be arguementive mind you, but if this IS viable ...
I don't have tons of money ... in fact I am going to have to limp along on the highway gearred factory 7.5" for awhile. The engine/transmission swap is already taxing my bank account.

I appreciate that you're trying to provide the info, but the wheels don't exactly bolt on if the extra 1.5" causes the tires to rub. Add in custom offset wheels to the $300 for the diff and $200 for the arms and now you're really close to the $800 for the correct G-body axle.

As an A-body guy myself, I'm very interested in $300 A-body posi axles. In my area (mid-Atlantic) you're looking at $500 and up for one. At $300, I'd buy it today. Heck the posi center section goes for at least that much.

 

[jrm81bu]

But if you are in the middle of a build and/or haven't bought your wheels yet then the extra width don't really matter. Or in my situation the wheels i have on the car will still work even with an extra 1.5"s per side. :wink:

 

[DrRansom442]

A-body and B-body rears are still consideribly cheaper around these parts than a G-body 8.5" ... not to mention a 12 bolt would be yet another improvement. If I can spend $300. on a differential and $200. on new control arms ... that is still cheaper than a $1000. rearend right? Wheels are bolt-on no matter what the offset, but only needed if I upgraded to a 5"x5" offset to use B-body parts. I am not trying to be arguementive mind you, but if this IS viable ...
I don't have tons of money ... in fact I am going to have to limp along on the highway gearred factory 7.5" for awhile. The engine/transmission swap is already taxing my bank account.

I appreciate that you're trying to provide the info, but the wheels don't exactly bolt on if the extra 1.5" causes the tires to rub. Add in custom offset wheels to the $300 for the diff and $200 for the arms and now you're really close to the $800 for the correct G-body axle.

As an A-body guy myself, I'm very interested in $300 A-body posi axles. In my area (mid-Atlantic) you're looking at $500 and up for one. At $300, I'd buy it today. Heck the posi center section goes for at least that much.

They probably are NOT posi ... I can live with an open rear ... but they can be found around here and at reasonible prices. 12 bolt still is a better differential than a 10 bolt ... so if you can install one for the cost of the other ... doesn't the 12 bolt still make more sense? All said and done if I can not find something cheap ... I will just have to not break the 7.5" till I can afford to order a custom third member.
I do know where there is a posi Monte SS 3:73 for around $350. but I'd still be in the same "durability" boat

 

[BrownGP83]

Just read this post and thought i would ask something. Are you going to be launching at the dragstrip or running slicks? Doing any hard roadracing? If your not, then I wouldn't worry too much right now. The 7 1/2 and 7 5/8 10 bolts are not the strongest rears in the world, but they are not made of glass. A mild 350 Olds is not going to shred one during normal driving. I understand wanting to upgrade to something better, but its not mandatory right now. I have a 3.73 rear out of a MCSS and i beat on it, but it holds up to my 383(fingers crossed!) without any upgrades yet. If i was you, i'd grab that Monte rear, throw it in, and have some fun!

 

[bigdan]

b body 8.5" out of a 9C1 cheap , 8.5" disc brakes + posi + sturdy 31 splines axles ....... (GN 8.5" dont have 31 splines have all been beaten to hell ..)

buy only fspecial ofset upper arms = 179.00 because lower will fit

american racing sells 6.75 back spacing wheels that fit this diff under a G body

Dan