LT1-LT4 Modifications 1993-97 Gen II Small Block V8

Rear end questions

Old 11-13-2013, 08:45 PM
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Default Rear end questions

As we all know, the stock 10-bolts in our cars are like glass. I plan on building my car into a street/show car. Mod plans are bolts and H/C. Maybe nitrous someday but that's only a consideration. 400-500 hp would be very acceptable to me. My question is, is upgrading the stock rear end absolutely a MUST when upping up the power? I am not dragging the car, so no launching or putting excessive stress on the differential. I only get on it from a roll (on-ramps for example). If I have to I'll go to a 12-bolt or 9 inch but if it's not necessary for my driving style then I wouldn't mind saving a buck and keeping the 10. What're your guys' thoughts on this?
Old 11-14-2013, 12:36 AM
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People usually claim that 6 speed cars have more issues with 10 bolts than autos because of the increased amount of "shock".

Typically people who have the most issues are people who drag race at tracks lot, especially on sticky tires/slicks.

When you say "add power" are you talking bolt-ons? nitrous? Stroker motor? It all depends on how much power you're talking about. Lots of people run 10 bolts well beyond 100k miles and don't have issues.
Old 11-14-2013, 12:50 AM
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Most upgrades are heavier, take more parasitic power/add to driveline losses and cost from $3000 to $5000 to install.

I kind'a like this idea to improve the stock rear with a late fourth gen rear: http://www.highperformancepontiac.co...d/viewall.html.

Ive dragged my car several times with MT radials and its held up. But i have and A4 car and mostly stock engine.

Good luck,
cardo
Old 11-14-2013, 07:14 AM
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it's really just a crapshoot. Some people (myself included) get lucky. some kill a 10 bolt with stock power on the street, and some beat the hell out of it without breaking it.

Mine's held up fairly well (except for ring gear bolts backing out once, which I think was the original installer's fault), and I have 4.10's, which have some fairly small teeth compared to stock. I beat the HELL out of it driving around on DR's and have been into the 10's with it, and it's still holding up.
Old 11-14-2013, 07:32 AM
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Keep sticky tires off it. Don't pop the clutch if it's a manual and you'll be fine. Thing is, if it indeed a manual you will definitely want to upgrade your clutch. Get a clutch with a sprung hub. An unspring hub tends to be extremely aggressive even with the simplest of clutch engagements. Big power is not what kills driveline parts. Shock to the driveline is what breaks parts. Friend of mine had an MTI 383 that went 12.0's @ 120 on the 10 bolt with Pep Boys Futura H rated tires. He drove the snot out of the car all the time. Only thing that kept the diff. from breaking is the crappy tires he put on. I wouldn't recommend it because you must be able to control that kind of power and crap tires can equal a rear end kicking out at high speed causing all kinds of trouble.
Thing is, getting heads/cam you'll also most likely want different gears to accommodate the power curve. Having someone do a gear install can cost somewhere in the 500/700/1000 dollar range. A new diff is probably about double that? I don't remember. So basically you are going to have to spend money on the driveline anyway... If you want to be frugal then yes, you can keep the 10-bolt and make it last, but you will not be getting the most out of your power curve even on the street. JMHO.
Old 11-14-2013, 07:54 AM
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I took mine to mid 11's with drag radials for three years, it was a high stall auto and tubes welded to center section with a girdle.
Old 11-18-2013, 05:28 PM
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Mine is completely stock with 3.42's and I run 315 nitto DR's without any problems as of yet doing many launches on the street but I have never been on a track. *Knock on wood*
Old 11-24-2013, 11:12 AM
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For your driving style you should be OK with the stock rear-end. I would recommend adding a rear-end girdle to help support the bearing caps and keep the gears meshed together under hard acceleration.

Later ... Larry S.
Old 11-25-2013, 12:25 PM
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Its each different persons experience. I've seen 10 bolts go into the low 12s on the regular and never break. I broke mine going from third to fourth on the highway when I had a hotcam and a D1SC. It all depends on when they let go, I can tell you one thing though now that I swapped to a 12 bolt theres no better feeling then leaving the line at 5500 and not having to really worry.
Old 11-28-2013, 11:07 AM
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There's lots of factors that play in to the role of a 10bolt lifespan. I killed one in a 88 formula running a stock 305tbi. That death was because a poor setup of 3.73's. If you stick with it make sure its set up correctly, even if its a factory rear that makes no noise have the set up checked.
Old 12-03-2013, 01:53 PM
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I have had five 4th gen Fbodys and four were m6s, with my first one I put Moser axles, billet caps, T/A girdle and 4.10 Richmond gears (about $1000 - $1100). I went to the track on DRs and about a week later I was simply pulling off from a traffic light and BANG broken ring and pinion which also took out the Torsen diff. I brought another set of 4.10's and a new Eaton posi another $800 and about a year later those Richmond 4.10's were howling so I got Motive 4.10's and a solid pinion spacer and stopped drag racing the car. Well when I got my next 4th gen the first thing I brought was the strongest rear available the S60 which has been swapped to each of my other 4th gen's and is currently under my Z28. I also just got a 97 m6 and I'm going to put an 8.8 Ford rear under that one so I can go as hard as I want and not wonder "when the 10 bolt is going to give up" because with the 10 bolt and m6 it's not a question of "IF" it's a question of "WHEN" it's going to BLOW UP.
Old 12-03-2013, 06:06 PM
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Originally Posted by 97Z28SS
... which also took out the Torsen diff.
Well there's your problem!
Are you sure it wasn't the other way around? My Torsen cracked in half when I was running 1.9 60' times.
Old 12-03-2013, 06:15 PM
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Don't ever buy a new 12 bolt they just cost way to much.
Old 12-03-2013, 06:29 PM
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I've had spider gears go out in my HD carrier twice now. Always a weak link.
Old 12-04-2013, 06:53 AM
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Originally Posted by 97Z28SS
I have had five 4th gen Fbodys and four were m6s, with my first one I put Moser axles, billet caps, T/A girdle and 4.10 Richmond gears (about $1000 - $1100). I went to the track on DRs and about a week later I was simply pulling off from a traffic light and BANG broken ring and pinion which also took out the Torsen diff. I brought another set of 4.10's and a new Eaton posi another $800 and about a year later those Richmond 4.10's were howling so I got Motive 4.10's and a solid pinion spacer and stopped drag racing the car. Well when I got my next 4th gen the first thing I brought was the strongest rear available the S60 which has been swapped to each of my other 4th gen's and is currently under my Z28. I also just got a 97 m6 and I'm going to put an 8.8 Ford rear under that one so I can go as hard as I want and not wonder "when the 10 bolt is going to give up" because with the 10 bolt and m6 it's not a question of "IF" it's a question of "WHEN" it's going to BLOW UP.
4.10 gears in a 10 bolt you are just asking for trouble. The size of the pinion gear is a joke.
Old 12-08-2013, 10:46 PM
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I had 4.10s in my 6speed Z, bolt on car 1 time on Drag radials and 3 times on Zr rated radials and the 4.10s sheered the teeth off........
As far as i am concerned the 7.5 and 7.625 rear end is 100% junk!!!!!! Never should have been placed into any performance orientated sports car ever....
I wanted a strong rear that i could get parts for easily so i chose the 8.8 route, my actual investment was 1/2 the cost of ANY aftermarket set up going...

In short why waste time with something that has been proven to fail? Even if you put a girdle on, aftermarket axles, good LSD you still cannot upgrade the part that causes the most grief and thats the diameter of the ring and pinion.........


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