I am about to put Nittos on my Iroc.. Its got a 3.08 gear set and a t-5 tranny, Pushing roughly 350 horsepower. Now, I know with the stock 10 bolt rear this is a sure recipe for disaster. Will I be ok if I just do some 12-1500 rpm drops? I know there is no sure way to tell, but my rear is in good shape presently (recent rebuild). Or should I skip the drops completely?

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Mike C
88 Iroc 5spd
355 TPI, AFR 190s and lotsa other mods
April feature ride at Sethirdgen.org

 

The combination for disaster is the tires and launch. I ran about 360+ on street radials at the track with a t-5 and stock 10.5 rearend and had no problem but.....traction. This is the key. If you decide to go much higher in horses there may be a problem.

 

I'd say the stock rearend is good for up to about 350rwhp max, with traction and hard launches. You'd still be pushing it, though.
I had 4.10's in my IROC and dropped the clutch at 5500rpms every time at the track, and usually got 1.8x 60-ft times. I had the metallic RAM clutch and T56 tranny.
Never once had problems with the rear, my car dynoed at 254rwhp/347rwtq due to the crappy stock TPI manifold.
That T-5 is another weak link, its only good for ~300rwhp max.


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-no more thirdgen-
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97' black Pontiac Trans Am
LT1, A4, free mods, CAI,
HPP3+, Flowmaster catback, 3.42's.
100hp Nitrous.

[This message has been edited by 89ROC (edited September 06, 2001).]

 

A stock 10 bolt won't survive long. The shock of high rpm drops with a manual transmission or using a transbrake with an auto will snap pinion teeth off in no time.

I still have a 10 bolt in my car. 4.10 gears, solid pinion spacer, LPW rear cover, 28 spline aftermarket axles, welded axle tubes. It's still surviving and I don't know just how long it will last. It could still last for many years but I plan on installing a 9" since I need to go to 4.56 gears with a spool.

High rpm drops will also destroy a T-5 as well as the stock clutch and flywheel.

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Follow my racing progress on Stephen's racing page
and check out the race car

87 IROC-Z SuperPro ET Bracket Race Car
461 naturally aspirated Big Block

Best ET on a time slip: 11.242 altitude corrected to 10.89
Best MPH on a time slip: 121.52 altitude corrected to 125.89
Altitude corrected rear wheel HP: 497.9
Best 60 foot: 1.546

Racing at 3500 feet elevation with a typical race day over 5000 feet density altitude!
Member of the Calgary Drag Racing Association

87 IROC bracket car, 91 454SS daily driver, 95 Homebuilt Harley

 

Very good answers guys, thanks. Thats exactly what I wanted to hear too. I think I will be ok for the drag meet I want to go to this weekend, as long as I dont beat on it too much. I was just concerned with the fact that I am putting Nitto drag radials on it now, I don't wanna pop an axle or pinion!

 

10 bolt,,,,ok in an auto, with 350hp,,and not a rev it up dump the clutch job,WITH big tyres,,once you get it out of the hole,there ok,give it heaps!! anyway they are cheap over there,,,so are 9" fords save the bucks,get a 9inch,,,,,till then dont go mad with the 10 bolt