Schurkey

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Schurkey, if you don't like Fords, just say it. The 8.8" is a perfectly good option, and is comparable in weight to a 10 bolt while being about as strong as a 12 bolt.
OK, I don't like Fords.

That said, not every part of every Ford needs to be immediately crushed. I have some respect for the Nine Inch, and I'll admit to jealousy over their aftermarket support.

The issue is that I don't even begin to understand why someone would custom-build a Nine Inch, or play games with an 8.8", when a carefully-selected Treasure Yard 9.5" semi-float drops right in to this vehicle like it was made to do so; has bigger/better brakes; and CAREFULLY SELECTED, may even have an acceptable gear ratio, leaving only the locking differential, some axle seals, and brake repair items as additional required parts.

Here's the rankings as I see them. Dana 60 (500 lbs) > 14 bolt FF (400 lbs) > 9" (400 lbs) > 14 bolt SF (400 lbs) > 12 bolt (230 lbs) = 8.8" (200 lbs) > 10 bolt (200 lbs)
I suggest a re-ordering, (based on typical "stock" parts) and with some additions: 10.5" Full Float = Dana 70 > Dana 60 = 9.5" Semi-float > Mopar 9 1/4 > Ford 9" = Mopar 8 3/4 = Ford 8.8 > Car 12 bolt > 8.5" 10 Bolt = Truck 8 7/8 12-bolt = Dana 44 > any 8.2" or smaller ring gear axle.

Aftermarket parts, OEM axle shaft variations (spline count, for example) could change the order I've presented.

I don't think the weights you have listed are accurate. But I can't find axle weights, so I have no evidence.

Randy (RIP) of Randy's Ring and Pinion says the 8.8 is equal to, or better than the GM "12-bolt" 8 7/8 ring-gear axle, due to larger axle shafts.

The 8.5" ring gear "10 bolt" is about the same strength as a Dana 44. (I say it's a fine small-block passenger-car axle, but not much of a truck axle. These, and anything smaller, have no damn business on a modern full-size truck.

"12-bolt" 8 7/8 ring gear axles were stronger in cars than in trucks due to the larger pinion diameter in the car axles. The truck 12-bolt got the same weak pinion diameter as the old 8.2" passenger car axle. OTOH, the car axle tubes were thinner than the truck tubes. (Torque, vs. load-carrying)
 

stutaeng

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The 14 b FF 10.5" is definitely stronger than a Dana 60:


They don't list the 14 b 9.5" in there though...Probably similar to a Dana 60, since both came with 3/4 ton applications (rear axle.)

Looks like the torque rating are as follows:

Dana 60 is 5,500 ft.-lb.

14 bolt:
9.5" = 5,000 ft lb
10.5" = 6,242 ft lb
11.5" = 8,321 ft lb

10 bolt
8.5" = 3,800 ft lb
 
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b454rat

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The 14ff is the king of the hill for rears. Even Ford and Dodge guys use em. Detroits are dirt cheap. At least used to be. Certain models of the Dana 70 are a touch stronger, but not nearly as common as the 14ff. Semi float 14b is not nearly as strong as a Dana 60. Not even the rears from Dodge or Ford with 30 spline axles, or even earlier ones with 16 spline. The biggest issue with the 14sf is the carrier, put a Detroit in n prolly be ok. 10 bolt and Dana 44 fronts are virtually the same axle. The later years of the front 10 bolts might be slightly stronger with the 30 spline, they were full diameter, didn't neck down the 44s do. It's hard to beat a 9" for a car or truck. They are strong in stock form. I'd rather run one of those than a 14sf. Forget finding a 14sf 5 lug, 454SS ONLY.
 

GoToGuy

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A couple of issues i see with with your theory's and formulations. 1. You should stay within his intended parameters. 2. A basic 8" Ford and basic 14 bolt. Which stronger? Under what conditions? Static loading ? Which breaks first? Under full load pull which spits the ring gear out first? With max static load under full power maximum pulling load. Who wins? With enough dollars and upgraded or custom parts you can determine whatever outcome you desire. It comes down to what does he want and what are his resources? I would opt for 14 bolt 9.5. Advantages are finding a 5 bolt or converting a 6 bolt. Why? He stated he worked a machine shop. Boom! Keeping all GM is a plus. Any small machining modifications are a breeze. 5 bolt axles are easily available. In any future modification removing and reinstalling the old rear axle set easy day. Keeping the 9.5 for other future project. Those conditions, set the 9.5 as a better, more economical choice. If at later date and intend full bore race like truck. Build up the Ford. Just a thought. Good luck, have fun!
 

Erik the Awful

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I don't think the weights you have listed are accurate. But I can't find axle weights, so I have no evidence.
I know the weights I have aren't completely accurate. I don't have examples of each of these to weigh, but I don't think they're incredibly far off.

Still, if Brad is planning on a 9000 rpm motor, anything heavier than a 12 bolt should be out of the question. I mean, we could throw the Rockwell on the list and blow everything else out of the water, but those basturds are 700 lbs. Good thing they have 6.72:1 ratios, because you're going to have that engine screaming to not get anywhere fast.
 

Nad_Yvalhosert

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When you say, “without the hubs sticking out on the center” do you mean a flat axle bolt flange?
No, he means a semi-float axle.

And OP is completely allowed to put a 9000 RPM engine in a truck with a Camper Special axle. Because "Death Race 2000" had a Ram Dually that would decimate the competition.
And somehow, it can keep up with a Mustang GT...
 
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stutaeng

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I have a 14b 10.5" with 4.10s/G80 with disc brakes I picked up for $180. I'm thinking of swapping it into my K3500. I'd weigh it, but I don't know how high my bathroom scale goes up to, LOL.
 

Schurkey

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I have a 14b 10.5" with 4.10s/G80 with disc brakes I picked up for $180. I'm thinking of swapping it into my K3500. I'd weigh it, but I don't know how high my bathroom scale goes up to, LOL.
Did the GMTs have discs on the 10.5" axles? I thought that was a GMT800 thing, except for rear discs on the C3500HD 11.5" axle.
 

stutaeng

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Did the GMTs have discs on the 10.5" axles? I thought that was a GMT800 thing, except for rear discs on the C3500HD 11.5" axle.
No. It came from a 06 2500HD...hence the "want" to swap for disc "upgrade."

My drums work well on the K3500, so I don't know if it's worth the effort though.
 
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