Anyone looking for a nice rear?

melloelky

Comic Book Super Hero
Oct 22, 2017
3,767
113
mass
sexy booty GIF

this^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ is the rear
 
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SS_Malibu

G-Body Guru
Sep 27, 2021
620
93
Mesa, AZ
That rear end works too as long as you don't have too much HP to break it.
And if you do, you can always swap it out.
 
  • Haha
Reactions: 1 user

565bbchevy

Geezer
Aug 8, 2011
9,196
113
Michigan
That rear end works too as long as you don't have too much HP to break it.
And if you do, you can always swap it out.
Just remember that you could break it and loose your axles and land on your quarter panels
 
  • Haha
Reactions: 1 user

jjjaffo

Not-quite-so-new-guy
Jul 2, 2022
35
8
Monroe Wisconsin
You know, I've always found this rear end debate interesting. Back in the early 2000s when I didn't know any better, I put a 408 BBC in my 1984 Cutlass. It was built up for fun street performance. It didn't take long before I blew the side gears out of a factory posi unit. I put another used factory posi in it and started twisting axles before blowing that posi all over the road. Like I said, I did not know a 7.5 rear was a bad thing at the time. So, I ordered new 28 spline axles, new auburn posi, and a set of Richmond 3.42 gears. Did the proper break in and proceeded to beat the car for the next 15 years with no rear end related problems. I had 255/60R15 on the back. Just pulled the drivetrain and sold the body to my friend who is putting a 454 in front of that rear end. Will it go boom? Who knows? All I know is I could light the tires for a city block through second gear and the rear never broke. I even had a shift kit in the turbo 400 that would snap your neck going into second. Even saw some track time, but could only muster a 13.1 due to a bad tune. Still, full throttle launch on a sticky track and a nasty smack into second gear and it stayed together. Cost me less than a grand to put that rear end together. So, my experience has been that the factory stuff is weak, but with good upgrades the "whimpy" 7.5 can take quite a beating.
Now that I've learned more about these rears I think it's a safer bet to put a 9 in my Elky due to the 489 BBC I will be putting in it. I'm not sure why Currie was the unit chosen for this discussion when QP makes an excellent unit for almost half the price. It's almost a no brainer if you want both new AND affordable to go the QP route.
 

Drkuhar

Master Mechanic
Sep 27, 2018
436
93
Girard, IL
I just ordered the quick performance gm 7.5 kit with posi carrier, solid pinion spacer 3.42 gears. My decision of the 9" was as stated in a previous post. Return on investment. Im not drag racing every weekend like i was 30 years ago when i had a 9" in this car. As a street cruzer with an occasional burnout, a mild 350, this will work for me. Even when i build my next engine, a 9" would be overkill for my use. Would it be nice (yes) is it needed for most peoples use (no).
 

Built6spdMCSS

Royal Smart Person
Jun 15, 2012
2,149
113
Florida Beach
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.
Auto is much more suttle on the drivetrain. The manual stuff tends to beat everything to pieces.
 
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69hurstolds

Geezer
Supporting Member
Jan 2, 2006
6,815
113
Every differential has its limits. It's your job to find out what that point is. I'm not downing 7.5, or 8.5, or 9s, or even 8.8s or whatever you want to run. My earlier point was that building a car is a complete unit sort of thing. You can spend as much or as little as you like. If you put the money in the wrong spot at the wrong time, though, you could be walking. Just as if you put a new Currie (or QP) 9" in your car, and keep the stock drivetrain? Why? If it's part one of a long term plan of building up the drivetrain, then you're likely doing it right and in the right order. If it's just cuz it looks cool and you now have steeper gears and no more plans to upgrade the drivetrain further, then put down the tools and step away from the car.
 
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69hurstolds

Geezer
Supporting Member
Jan 2, 2006
6,815
113

is that a Quick Performance or a Strange Engineering built rear?
Not sure, probably wouldn't be able to tell until you "pop the cover" and get in there and root around. But I'm betting it's sturdy, high quality, and wouldn't be cheap. Make sure you use the proper lube. ;)
 

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