GOLD85

well how strong are they. i'm planing a 406 swap in the spring as well as swaping out the old one legger 3.42s for some 3.73 or 4.10. the 406 should be close to 450 foot punds of torque. the thing is i dont want to invest in a set of gears and a posi unit and then strip my axels. also, do IROCs and GTAs have 28 splin axels and to the all have posi. thank you for your help.

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when the green flag drops the bull$hit stops

350,performer RPM intake ,650dp, 700r4, headers, 3inch exhast

Baz89RS

As long as your changing the gears and posi, go for the newer 28-spline axles... That's what I did and the shop got them for me from a yard at $50 a pair, i'd say that's fairly cheap insurance(comparing to the money for the gears and posi)... and they'll hold up just fine.

ede

i don't think the 26 are any weaker than 28's, it's just that the posi units for the 28 spline are much better. i agree buy the 28's and the posi to match.

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ICON Motorsports
1st & 3rd

AlkyIROC

You'd probably break the gears before you break an axle. It's easy to swap to 28 spline axles. Even better aftermarket 28 spline axles are only $125 US each. www.drivetraindirect.com has them. Part number KAC7-A7

If you don't dump a clutch at 4000 rpm or use a transbrake then even 26 spline axles should hold up. It's the shock load that breaks the axles. Putting power through a normal automatic tranny or slipping a clutch won't put that kind of shock load to the axles.

Many of the IROC and GTAs came with 9 bolt diffs. I think these are 27 or 28 splines. I never pulled my axles to see. Somewhere around 88 or 89, the 10 bolts went from 26 to 28 spline. 93 and up are 28 spline but the axles are longer.

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Stephen's racing page

87 IROC-Z Pro ET Bracket Race Car
383 stroker (carbed) with double hump cast iron heads and pump gas
454 Big Block buildup now in progress for the 2001 racing season

Best results before the 383 blew up
Best ET on a time slip: 11.857 altitude corrected to 11.163
Best MPH on a time slip: 117.87 altitude corrected to 126.10
Best 60 foot: 1.662

Racing at 3500 feet elevation but most race days it's over 5000 feet density altitude!
Member of the Calgary Drag Racing Association

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

[This message has been edited by Stephen 87 IROC (edited December 13, 2000).]

82camaro

The added 2 splines aren't going to give you any more strength, the axle breaks it's not going to be from the lack of 2 splines. Chances are you will tear up the gears before anything else. Get the gears you want, install a powertrax locker in your existing carrier, the thick rear diff cover with the bearing preload, weld the axle tubes to the housing, install all new bearings. How long it will last depends on how hard you run it and how much traction you get(along with lots of other variables.

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82 camaro--original steering wheel, brake/gas pedals, seats--everything else modified
82camaro

bjankuski

28 spline axles are 18% stronger then the 26 spline axles. The spacing between the splines is the same so the two additional splines can only be addded by increasing the diameter of the axle. The additional increase in diameter (even though it seems small) adds 18% more strength.

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1988 Formula 5L/5sp 3.45 gears, SLP cold air kit, MAS gutted, TPIS air foil, TPIS AFPR, MAC headers, Mac under drive pulleys, MAC cat back, Relocated MAT.
Best ET street tires 13.85
Best 60 FT street tires 1.930
Best MPH street tires 99.29

irocnroll89

iTrader: (4)

i spoke to a guy from RANDY's RING and GEAR, Concerning my rebuild up(see my other post) and he said the 26 spline would be good in to high 12's. So my opinion would be if you have the money and need a new carrier then upgrade, but save your money if you only need gears. This reply goes more to the folks that are looking to upgrade for the sake of doing it. Good Luck to all

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'89 SHAGGY IROC
L98 7r4, all free stuff,T.E.S.,HOOKER CAT BACK,KYB,ACCEL8.8,JET fan sw. etc.
so much to do , so little money