I understand and agree they are great but I`m sticking to the 8 3/4 for now and know of low 9 second cars running 8 3/4`s w/success and it will get lighter.......

This HD nodular iron 489 case has the same heavy forged steel caps (with allen bolts) used on 3.25" bore 9" castings. In addition, the casting is much thicker than stock and it does not have any ID numbers on the side. They have been on the market for about 3 years.

Right, I'm just helping Thumperdart justify it as a Mopar rear axle lol.

So what`s the story Cass about yukon rating em at 500 hp?

Rating by HP is pretty silly.
What breaks gears is weight + traction + starting line torque (+ trans brake, if used). Peak power has nothing to do with it.
High 7 second turbo Powerglide Fox bodies use the original (modified) 8.8 axle.

That`s why I asked the question and was told loading and unloading the tires has a greater impact than dead hooking and my 4x4 friends snap axles on a continuous basis when the tires leave the ground then slam back down under power. Bottom line...........are the Cass nodular center sections stronger than the factory units?

How many runs were you getting out of the stock rears.......

I think the main 2 weaknesses of an 8 3/4 are the caps and the housing flex. After those are fixed, then its the pinion and then the ring gear teeth are small.

Agreed and my stock length a-body housing has a back-brace but still has stock caps............

Nodular cast iron, also called malleable iron, has 50% more stiffness than gray cast iron. It also has more tensile strength than gray cast iron.

That means that if the new nodular cast housing was exactly the same as the OEM gray cast housings, it would be way stronger.

Since we have been told that it is a beefed up casting, as well as being Nodular, it is way, way stronger than a stocker.

It is the gears trying to push apart, as mentioned above, that causes most failures. A stiffer casting will resist more force.

Back in the day, racers who were into the 9" looked for the "N" on the casting to pick the most desirable ones. That was before you could order any 9" part from a catalog.

R.

THIS is the kind of info we need to know and follows up on everything I`ve read in the last few weeks along w/talking to Cass.......

Cast steel is way stronger than cast grey iron, stronger than cast ductile iron and cast compact graphite iron My message is almost all the above except cast grey iron are stronger than what GM and Ford used in the stock production rear ends, Mopar put the better stuff in our third memebers

So then are we in agreement that nodular is stronger than all of the above?

slam back down under power

Definitely, all of the rotating energy of the tires, wheels, axles etc. already up to speed - and the tire contact patch connects to the chassis, which is almost stalled.

This was famous for breaking motorcycle transmissions. When the rear wheel went airborne (a jump) and the rider didn't roll the throttle off - the case explodes as the gears try to separate to relieve the stress.

AFAIK steel is highest.

As in stock 3rd members?

Thumper. I believe that with your current weight status and only going lower, plus unnecessary abuse of it (ie; Showing off burnouts, not warming it up prior to a run, Trans brake)will keep that Nodular rear around for some time.
Keep the abuse to heating the tires and racing only and it will survive. Now if you were at 3600 pounds and up while hooking hard, I'd be nervous.

THE weakness of the 8.75 is the case itself and the pinion stem. The torque flexes the case and lets the pinion move away from the ring gear, which shells gears. When you get that crap going on, it pushes the cap off, as the mashed teeth are trying to roll over themselves. The billet cap will maybe keep it from breaking the cap, but does NOTHING to address what caused the failure in the first place, which is case and pinion stem flex.

This is where guys say that the 8.75 pinion stem is about the same as DANA, which is true...........BUT, the DANA housing is massive AROUND the pinion, which helps support it and the case doesn't flex. You can't do that around the pinion in an 8.75, because it's a drop out . You CAN make it out of a little better metal, but you can't increase the support area. So the drop out is better, but not FIXED

I think housing flex is the reason for cap breakage in a lot of cases.

Have you ever tried a 4.10 gear?