Anyone looking for a nice rear?

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81cutlass

Comic Book Super Hero
Feb 16, 2009
4,639
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Western MN
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.

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Built6spdMCSS

Geezer
Jun 15, 2012
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Definitely will save money setting up your own build, then again just depends on what you know and what you have access to.

I'd run a built up 7.5 behind an auto car all day that's 500hp. Stick car, yea it'll beat it apart eventually.
 
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blk7gxn

Royal Smart Person
Feb 7, 2019
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So I redid according to your requests. It doesn't come painted as you stated, and chose the cheapest possible options. Still 5k. Just not understanding how that is a deal over a much cheaper 8.5" Not picking anything apart, just stating facts.

I can understand your point your trying to make, and to be honest, it may not be a deal to everyone, maybe someone has access to an inexpensive 8.5, and if so, by all means build it! ...on the other hand, not everyone has that option or skill level to build one, maybe there are fellow G body brothers or sisters looking for a 8.5 and are being faced with the crazy prices people are asking. If someone actually did choke up 2-2.5K as I have seen being asked, they still have to build according to their build $$$$ and the time invested is also a factor for some.
I personally think its a good deal if someone had to go the latter of the two options. This is my opinion, doesn't mean you have to agree. I found with myself, and watching others builds, you always end up spending more than anticipated, and there's always that " finding time factor " too. I hope by sharing, it may help someone down the road on their build, its always nice to have options. With no disrespect, I'm done defending my post, there's always someone going to disagree with opinions, and that's ok, it what makes this site great, because at the end of the day we are all a family here with the same passions and love for our beloved "G's" .
 
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2ABodies1FBody

Not-quite-so-new-guy
Nov 5, 2014
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Built6spdMCSS

Geezer
Jun 15, 2012
5,695
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Florida Beach
I'm done defending my post, there's always someone going to disagree with opinions, and that's ok, it what makes this site great, because at the end of the day we are all a family here with the same passions and love for our beloved "G's" .
Family is a strong word for some here..🤣
 

Ernest

G-Body Guru
Apr 28, 2016
718
959
93
Texas
Definitely will save money setting up your own build, then again just depends on what you know and what you have access to.

I'd run a built up 7.5 behind an auto car all day that's 500hp. Stick car, yea it'll beat it apart eventually.
Out of curiousity... are there truely any performance parts for the 7.5" differentials?
 

Cauterize

Floater of Valves
Supporting Member
Feb 9, 2019
509
1,528
93
Deathbridge
Out of curiousity... are there truely any performance parts for the 7.5" differentials?
While many will say "don't waste your money on upgrading a 7.5" There are options out there.
Upgraded axles woth higher spline counts and carriers to match as well and many gear set options.
These can address some issues. But what really kills a 7.5 as mentioned before.. grip and torque. Mild street car with normal tires and a reasonable stall shouldn't have any problems.
 
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Ernest

G-Body Guru
Apr 28, 2016
718
959
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Texas
I wouldnt mind going that route someday, upgrading my 7.5" with higher splined axles, a performance posi diff and 3.73 gearing on street tires only with my ZZ4 or with a 383cid max and 700r4... power adders, slicks and race track passes need not apply.
 

ck80

Moderator
Moderator
Supporting Member
Feb 18, 2014
5,742
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I wouldnt mind going that route someday, upgrading my 7.5" with higher splined axles, a performance posi diff and 3.73 gearing on street tires only with my ZZ4 or with a 383cid max and 700r4... power adders, slicks and race track passes need not apply.
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.
 
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Clone TIE Pilot

Comic Book Super Hero
Aug 14, 2011
3,828
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Galaxy far far away
it is wild what the 8.5's are bringing.

I even see posi 7.5s going for pretty crazy prices now. Glad I got mine with a 3.73 ratio for $100.
 
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