9" swap suggestions

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Sheps78

Not-quite-so-new-guy
Dec 28, 2017
8
3
3
Ive got a 78 el camino with a big block making about 500 hp and a th350 behind it. Currently still on the stock gm 7.5 rear and been tossing around my swap options. It wont see the track every weekend but id like to have some piece of mind it wont fly apart when i launch it. I only drive it around town really every once in awhile so 55 mph is about all it sees. Looking at getting this housing ready to go http://www.quickperformance.com/QP-GM-1978-1987-G-Body-9-Inch-Housing_p_10.html just needing some pointers which upgrades i should choose when i order it to make this as simple as possible installation and what length axles i will need as well. I can get my hands on a third member pretty cheap so not worried about that. And also reccomendations as to what upper and lower control arms to run. The springs and shocks on the car now are pretty new so I'll probably just reuse those for a little while. Like i said im not a hardcore racer id just like to be able to take it out and have fun with it and not worry about axles and gears breaking.
 

565bbchevy

Geezer
Aug 8, 2011
9,618
12,699
113
Michigan
I would go with their housing and axle kit assuming you know your spline count.
http://www.quickperformance.com/QP-GM-1978-1987-G-Body-9-Inch-Housing-Axle-Package_p_63.html
I knew I was going to run Wilwood rear disc so when I ordered my rear (mine is a Moser) I got the Ford big bearing ends to match up with my brake kit.
Make sure the case for you 3rd member is Nodular Iron since stock cases can't handle much power.
Any aftermarket rear control arm for a Gbody will fit directly to your 9" even your factory ones. But I would get adjustable uppers with roto or Johnny joint.
If you have welding and fabrication skills you can weld your own rear brace, drain and fill plugs etc. like I did on my bare housing and save some money.
I also used POR 15 on the housing instead of paint or powder coating and it is still holding up 18 years later.
IMG_0015.jpg
 
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1badgbody

Not-quite-so-new-guy
Jan 30, 2018
36
23
8
Buffalo, NY
With what you have, you will be ok with the 7.5". They're not great but they are a lot tougher than what most people say. If you up the horsepower any and plan on dead hooking then I would consider an upgrade but I would leave what you have alone, it will hold. I've made hundreds of passes on 7.5" rear ends pushing 500 hp with no issues, I only stepped it up when I started spraying. Don't bother with an 8.5" out of a grand national or 442, they're not much better than the 7.5" and not worth buying and swapping. If you're dead set on swapping the rear end then be patient and wait for a used Quick Performance 9" rear end to pop up for sale. That's what I did. I picked up one for $1,000 and another for $1,200. They would have cost just under $4,000 if I would have ordered them. The Quick Performance 9" rear ends are excellent pieces, they bolt directly in and fit perfect with absolutely no modifications. If you're going to order a piece, get the worm drive, not the clutches. If you're going to go through the trouble of the swap then break out a few more hundred and get some UMI tubular control arms, adjustable shocks and a good set of springs (I've had excellent luck with the Moroso trick springs). No point in upgrading the rear end without upgrading the stuff that holds it in and the car up. But again based on what you said, leave the 7.5" for now and drive the m'fer.
 

lilbowtie

Comic Book Super Hero
Jan 7, 2006
3,460
3,965
113
Canton Mi
If you are only running around town on street tires the 7.5 has a chance. I'm only putting down 450 HP and a no way is a 7.5 going to live. I run a Moser in the Regal and a Quick Performance in the Sonoma, no complaints. Just because you buy a nine don't think it's bullet prove. You need educate yourself on the center section as to what your doing and hp. Mainly what case to use, what gears, splines, bearing size, pinion support, and yoke.
 

michmalibuman

Royal Smart Person
Jun 14, 2017
1,040
1,154
113
All good advice, I just ordered a Quick Performance for mine.:cool:
 

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ham1974

Greasemonkey
Oct 6, 2012
240
66
28
With what you have, you will be ok with the 7.5". They're not great but they are a lot tougher than what most people say. If you up the horsepower any and plan on dead hooking then I would consider an upgrade but I would leave what you have alone, it will hold. I've made hundreds of passes on 7.5" rear ends pushing 500 hp with no issues, I only stepped it up when I started spraying. Don't bother with an 8.5" out of a grand national or 442, they're not much better than the 7.5" and not worth buying and swapping. If you're dead set on swapping the rear end then be patient and wait for a used Quick Performance 9" rear end to pop up for sale. That's what I did. I picked up one for $1,000 and another for $1,200. They would have cost just under $4,000 if I would have ordered them. The Quick Performance 9" rear ends are excellent pieces, they bolt directly in and fit perfect with absolutely no modifications. If you're going to order a piece, get the worm drive, not the clutches. If you're going to go through the trouble of the swap then break out a few more hundred and get some UMI tubular control arms, adjustable shocks and a good set of springs (I've had excellent luck with the Moroso trick springs). No point in upgrading the rear end without upgrading the stuff that holds it in and the car up. But again based on what you said, leave the 7.5" for now and drive the m'fer.
Were are you finding the quick 9 used? eBay?
 

airboatgreg

Comic Book Super Hero
Oct 2, 2016
2,870
3,116
113
Ive got a 78 el camino with a big block making about 500 hp and a th350 behind it. Currently still on the stock gm 7.5 rear and been tossing around my swap options. It wont see the track every weekend but id like to have some piece of mind it wont fly apart when i launch it. I only drive it around town really every once in awhile so 55 mph is about all it sees. Looking at getting this housing ready to go http://www.quickperformance.com/QP-GM-1978-1987-G-Body-9-Inch-Housing_p_10.html just needing some pointers which upgrades i should choose when i order it to make this as simple as possible installation and what length axles i will need as well. I can get my hands on a third member pretty cheap so not worried about that. And also reccomendations as to what upper and lower control arms to run. The springs and shocks on the car now are pretty new so I'll probably just reuse those for a little while. Like i said im not a hardcore racer id just like to be able to take it out and have fun with it and not worry about axles and gears breaking.

I am doing this swap next week as time permits on my 82 El C. I went with a 370 gear, rear disc and 2" wider. While doing this swap I am replacing springs, shocks and adding a rear sway bar. Will keep all posted on project. I bought mine from Quick and impressed by customer service and quality as I am a bit picky so to speak. I had to return mine as they sent a stock width and they were great. If you order go with the additional port for the gear oil. I wish I did.
 

michmalibuman

Royal Smart Person
Jun 14, 2017
1,040
1,154
113
I am doing this swap next week as time permits on my 82 El C. I went with a 370 gear, rear disc and 2" wider. While doing this swap I am replacing springs, shocks and adding a rear sway bar. Will keep all posted on project. I bought mine from Quick and impressed by customer service and quality as I am a bit picky so to speak. I had to return mine as they sent a stock width and they were great. If you order go with the additional port for the gear oil. I wish I did.
Keep us posted I'm waiting for mine.:cool:
 
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