If I put 4.10 gears with 15" x 10" rims with radials, what else besides 31 spline axles do I need to keep from breaking my rear end (with only a few bolt ons)? Do I need a LSD?
What will I need if I plan to blow my car (Centripetal, 10 psi max)

 

It's not really the gears or the tires that are breaking axles. It's the tires. Cars with just a few bolt ons can break axles running slicks. If you run street tires then your current axles should be fine. But if you decide to beef up the rear end, you can't change to to 31 spline axles without also changing to a 31 spline differential. If all you want is stronger axles you might try these:

http://www.americanmuscle.com/moser-...axle-9904.html

 

ok, thanks.
do you think the forged 28 spline axles will hold up with good thick DR's (10 inch rims) and 400 rwhp/trq? that's a lot of torque and a lot of tire.

 

Honestly if you want to do it right the first time and have that extra peace of mind knowing you went with the better setup, get a full 31 spline setup from FRPP, including the differential. I say skip the hardened 28's. My axles and differential were just over $500 brand new. They also take 5k+ clutch dumps on 315 BFG drag radials and 4.30's.

 

31 spline differential and axles shouldn't have a problem holding that. Even with the blower power (it's centrifugal btw) it should be fine. A differential girdle would be a good idea too.

 

Skip the 28 spline hardened axels and just buy the stuff through frpp. like said above, under $600 for a total rearend upgrade. and you wont have to worry ever again about snapping anything.