HI
anyone use a 8 1/4 rear 4:56-4:88 for drag racing with slicks 4000lb car? 400-500 hp mark Williams can make axles for me 27 spline
thanks gary

I think you would be better off spending your $ to upgrade to a better/beefier rear end. I just don't see a 8 1/4 lasting very long under those conditions.

using for nhra stock, can get S60 from doctor diff, kinda heavy plus takes extra hp to turn

But you'll never break it.

Would a Chevy 12bolt rear be legal in your class? I remember several years back a few guys were using them in some Hemi Abodies. They are lighter than a Dana,absorb less power than a 9inch (attractive to a class racer)
and tons built. Should be able to build one to easily handle 400-500hp reasonably.Lots of used stuff also. Just a thought -if it's legal for your class. Bill

Legal super/stock, stock no needs to be same make as body

I can deal with changing ring and pinion each season as maintenance, just don't want to spit out pinion on starting line

i ran a 8-1/4'' for years behind a 410'' stroker in my 3980 lbs. Aspen R/T. around 450 hp. 28/9/15 MT slicks

What about an 8.75? Those can be had for cheap. I'd feel much more confident w/ that.

if race only buy the 35 spline spool and axles and a steel cap for the drivers side and maybe a back brace if the car hooks and 60 ft. real hard

Saw your thread on classracer.com too.

I believe you would have to get a c-clip eliminator for the 8 1/4" rear because I'm pretty sure they are illegal (unsafe) under NHRA rules.

As mentioned by others, a Dana 60 won't slow you down much, if any at all. Most people I've heard commenting on the change didn't lose anything and some claimed to be slightly faster! It is a more efficient rear than the 8 3/4" (Takes less HP/torque to turn.) because of the location of the pinion contact relative to the ring gear. A Chevy 12 & 10 bolt are more efficient and a Ford 9" is the worst, but of course they aren't legal. 81/4" might be pretty efficient, but weaker, minimal ratio choices and fewer aftermarket parts. Overall weight is really irrelevant because the car has to be run at a minimum weight with driver anyway. Plus, the weight is in the back where it will do the most good. When you start replacing internal parts with aftermarket pieces that are lighter, the weight difference between a Dana 60 and 8 3/4" shrinks - (i.e.:lightened ring gear & spool, ) because the Dana 60 parts weigh more to begin with. Axles can be drilled and lightened in the flange area in either type. You also don't need a back-brace for a Dana 60 like you should have for an 8 3/4", bringing the 2 even closer in weight. Only down sides I see is that you need to get the gear ratio correct the first time and swapping gears is not as easy. Easier to get PRO gears for a Dana 60 as well. But either can have cryo and/or Superfinishing done for longer life.

I believe in the benefits of a Dana 60 enough to have installed one in my K/SA Aspen Wagon.with a 360 at a minimum weight of 3,927 starting out in the 12's! Got one for my trusty Dart Sport @ 3,530 minimum weight for IHRA Stock capable of low 11's. But that one hasn't been installed yet and don't know if I'll be out with either one anyway.

Get a Dana 60. It will be better and cheaper in the long run.

I don`t think anyone sells a c clip eliminator for a 8 1/4. I looked some years ago and never found one.