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.
------------------ 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).]