Anyone looking for a nice rear?

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Built6spdMCSS

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Jun 15, 2012
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spongbob

Greasemonkey
Oct 1, 2022
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The cheapest route is actually going with a late monte carlo ss. Not sure the year they started, probably 86 or 87, but for sure 1988 had a 7.625" rear with 28 spline axles. No, it's not the same as going into the 30s with a 9", but, it's a cheap bolt in considering it comes with 3.73s. If you were going to do the mild 7.5 build treatment, I'd start with one of those instead.
Isn't harder to change a unit then swopping a gear set would be for and old guy
 

Built6spdMCSS

Geezer
Jun 15, 2012
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Changing the whole rear end out is more heavy work than compared to just pulling brakes, axles out, driveshaft off the yoke and pulling the center section out if you have the 9" setup. If you have a lift it's much easier for the 9".
 

64nailhead

Goat Herder
Dec 1, 2014
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Isn't harder to change a unit then swopping a gear set would be for and old guy
Swapping an entire rear that uses the original a-arms is stupid simple and can easily be done in 2-3 hours with a jack and 2 jack stands. Rebuilding a worn out 8.5 differential with new gears (and bearing kit) and installing new drum brakes is much more time consuming.

The biggest butt ache with swapping different type (brand) housings is the driveshaft, especially if you have a non factory transmission. Every modification requires a different length driveshaft. With that in mind, I have a properly built 7.625 in a factory g-body housing the basement as a spare. And I have the driveshafts to swap in as well for my son’s 200-4R setup and my 4L80.

Do I need this crap sitting around…..refer to the hoarding thread haha.

spongbob - glad you revived this older thread - there is some great info in here. Jake’s (81cutlass ) 12 bolt is about the most ingenious setup I’ve seen, especially considering it’s a ‘one off’ I believe.
 

SS Elco

Not-quite-so-new-guy
Aug 3, 2017
35
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8
I got basically the same 9" rear from Quick Performance w/ disc brakes for about $2300. Nice looking unit that I'm pleased with.
 

SS_Malibu

Royal Smart Person
Supporting Member
Sep 27, 2021
1,183
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Well after reading through this thread, I'm a lot more comfortable with my factory 7.5 Posi unit (freeway gears for now) in my '79 Malibu. I have the Blueprint 383 in mine and while it's 450 HP @ 6000 RPM's I'll never take it there. It's just a fun car to enjoy. The mildly built TH350 trans and rear gears will eventually be switched but I get enough enjoyment from it either way. If anything was to break with the trans or rear end then it will get moved up the list. Until then, I'm just gonna enjoy it.
UPDATE:
The trans broke. (like I knew it would) I just thought I would get a few more miles out of it first. Anyway, it's moved up the list. Ordered a TCI TH400 a few weeks ago. It should be shipping soon, (for crying out loud)
 

doood

Amateur Mechanic
Sep 24, 2020
591
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Is a new crate 9" a good option? Yes.
Is it affordable? It depends.
Currie, Quick, all sorta people make one. Potato/po-tot-oh

Personally I don't like the 9" ford base design rear, just preference thing. There are some design related thing's I don't like (inefficient compared to other options) but my biggest gripe is the market. I think also a ton of people spend a ton of money on a 9" when the car will live on street tires, jack stands or the garage it's whole life. If you aren't clutch dumping at 4000+ rpm or on sticky tires a 7.5 in good mechanical shape is FINE for 95% of the population.

Used 9" 3rd members that cost $1000 to set up are worth $850 after 3 years of merciless beatings at the drag strip, sorry dude, that's not the case. There is wear and depreciation.
There isn't a factory 9" left in the junkyard that has a gear ratio, width, axle spline count, diff carrier or brake style that's right for any performance application (G body, nova, Fox, hot-rod)

A currie/quick 9" has as much in common with a ford 9" as a Dart or SB2 to a OEM GM SBC.


Does time have a value of money? Sure. But, there are a lot of hidden costs with a 9" that seem to get glossed over. If you are charging yourself to work on your own car I guess, but I've never paid myself to set up my own gears or weld my axle tubes.

However I went the total bonkers route 99% of people can't do so I'm a bit in left field.

Buy $75 zr2 8.5 rear, factory disk/30 spline/g80/3.73 rear from salvage yard
Hummer H2 AAM $50 forged 1350 yoke
Cut the tubes off the 8.5 and sleeve in 7.5 tubes $free
Swap zr2 brakes onto g body tubes, new rotors & pads for $50
Moser 30 spline G body axle shafts $280
Moroso studs $35
Pick your poison of posi carrier (yukon, OEM posi, trutrac) $free-$450
Use 3.73 gears or swap to your ratio of choice $free-$250
$35 rebuild kit from QP
$25 of brake line from the vato-zone, oh-really's, or NA-PAW
Design an UCA bolt on flange and machine on your buddies CNC bridgeport, hey that one was fun! $40 drop steel + $25 endmill + some welding gas & wire, $50 for spherical upper bushings

But I can watch people's eyes glaze over when I tell them what it is which is worth it to me.
This is awesome. You should make more and sell.
 

81cutlass

Comic Book Super Hero
Feb 16, 2009
4,654
13,595
113
Western MN
This is awesome. You should make more and sell.

Thanks

I had planned to build some but I had some reliability issues keeping this rear end together. Not a fault of the axle, just I am very mean to it with 3750lb, 4000rpm clutch dumps, lots of torque with a supercharged large cube motor, sticky tires on great tracks and drag and drive punishment. I split a Yukon posi case in half, twisted Moser 30 spline axles, bent studs and twisted a slip yoke. Not 8.5 rear reliability issues, just my being a hooligan.

I also was CNC'ing it on a friends mill but he sold it and farming the machine work out eats into my profit and it's a lot to manage.
 
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