Upgraded 7.5

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LsxBuickRegal1982

Greasemonkey
Nov 9, 2018
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I will be upgrading my 7.5 rear end with 28 spline moser street axles and a Torsten zexel differential
AD7F6C8F-9E29-4864-AEE3-A0A9771BA44B.jpeg
from a 4th gen f body plus a perfect launch diff girdle I’m wondering will it hold up with my ls 408 striker
 
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pontiacgp

blank
Mar 31, 2006
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GM to put it behind an LS1 with a warranty but they did not have the hp your 408 has. Why didn't you go with a better rear end instead of putting money into a 7.5 and wondering if it will hold up
 
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Doug Chahoy

Comic Book Super Hero
Nov 21, 2016
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I don’t know what you have $$$ in parts, but my QP 9 is coming today for $1,820.00 to my house. And I don’t have to hope it holds up. Good luck though
 

LsxBuickRegal1982

Greasemonkey
Nov 9, 2018
133
128
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I was in a rush and now I’m kicking myself in the *ss I’m just now seeing the price of a Quick Performance 9” plus I have my Nitto Nt555r drag radials
 

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Gonzo1970

G-Body Guru
Sep 30, 2018
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I am in the same boat with the 7.5 "Question"

The research I did concluded with this:

IF you upgrade a 7.5, go with 28 or 30 spline Axles.
IF you're going to push 400 or more TQ/HP, DON'T use the 7.5.
IF you run a 7.5 Posi with any kind of power in front of it DON'T let it wheel-hop.

Ive seen people have great luck with the 7.5 and high numbers (eg. 400+), even drag race it.. But, those success stories are way, WAY fewer than the number of "Grenaded" 7.5 stories.

Personally, my goals are running the stock 305 until it pukes then just get a mid-late 70's 400, rebuilding it conservatively, and just letting it breathe. (Just a nice little street runner, not a Z06 Eater) so the 3.73 Posi with 28 spline Axles would suit my purposes.

-Gonz
 
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pontiacgp

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Mar 31, 2006
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I've been there and done that....those axles could be an upgrade for an 8.5 and there should be a market for the carrier so if I were you I'd cut my losses and sell what you have and get something that will fit the package.
 

DRIVEN

Geezer
Apr 25, 2009
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*CENSORED*
Really only one way to find out.

I'll be going with a QP9 in my car though.
 
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Blake442

Geezer
Apr 24, 2007
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Minneapolis
On the street you'll be fine...
Hit the track with drag radials or slicks and it's just a matter of time.
I'd go 9"... 7.5's and 8.5's are a waste of money if you wanna go fast.
 
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Doug Chahoy

Comic Book Super Hero
Nov 21, 2016
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In all my reading the engines the 7.5 were put behind only developed at most around 200 hp. Even a stock 8.5 was only behind under 300. I’ll not regret going with the 9. I just hate the fact that it’s a FORD. But hell look at all the people putting Chevy engines in Fords. And using a Chevy created cowl hood.
 
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pontiacgp

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Mar 31, 2006
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as far as a 7.5 upgrade that is a good upgrade so like Blake442 posted on the street it'll work great......is your engine the 600 hp version?
 
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