SRW to DRW GMT400 K3500; later model rear?

[BNielsen]

I'm slowly in the process of taking my 2000 Chevy K3500 SRW and swapping it it to a dually; really would like to swap to a later model rear end with disc brakes as the options for DRW conversion kits aren't as appealing as what's out there for SRW.
Like everything else, I've been trying to pinch pennies for this swap, and the axle seems to be the next biggest hurdle.

The 11.5 AAM seemed to be the best option as far as the availability of the axles from junkyards/wreckers/people parting trucks out, but I stumbled upon this on marketplace
14-bolt, I'm assuming 10.5 ring and pinion, factory disc brake DRW axle.

I messaged the seller and asked for a few other dimensions, he stated it came out of an Express Ambulance cutaway; the overall width of the axle being 75 inches eased my concern with it being listed as a C&C rear.
Seller sent me a photo of the stamp on the axle, but wasn't able to inform me of gear ratio

I don't like asking these kinds of questions, but I've exhausted most search avenues regarding the specs of this axle, punching that SN in on AAM parts lookup doesn't send back anything, and I'd seen some vague posting about the commonality of a 14-bolt disc as a majority of the newer dually Express chassis' came with Dana rear axles.

Is there any reason this axle wouldn't be a good fit to swap in my truck? I wasn't aware of there being a factory 14-bolt DRW, and truth be told as beefy as the 11.5 is, I do occasionally get off into less than ideal terrain.
A CCLB is already a cumbersome unit to mob around; a crew cab dually pick-up (a piece of automotive art) brings forth an entire new set of navigational challenges, but at least with a 10.5 to 10.5 the ground clearance is the same, at least my mental gymnastics have gone with this reason as justification.

 

[zuke]

If everything is as it should be and the axle truly came out of an Express Ambulance cut away, then federal regulation would apply, which specifies that the gearing should be the lowest available from the chassis manufacturer. So it should have 4:10 gears in it.

That said, I've seen that particular regulation ignored more than once....

 

[BNielsen]

If everything is as it should be and the axle truly came out of an Express Ambulance cut away, then federal regulation would apply, which specifies that the gearing should be the lowest available from the chassis manufacturer. So it should have 4:10 gears in it.

That said, I've seen that particular regulation ignored more than once....

I'm assuming the ratio should in theory be stamped on the ring gear? I wouldn't be bothered if I had to throw a gear set in, having 4.10s already would definitely be nice but isn't a deal breaker if not.

 

[zuke]

It would be stamped in the ring, yes, if you're in there anyway, And you could also count teeth if you've opened up that axle.. (Which I would guess you will be before installing it)

 

[Clubbs]

Another thing to not is if you're switching to rear discs from drums then I think you'll need a different brake proportioning valve. Drum brakes require a 10psi check valve to keep the wheel cylinders from retracting with the force of the springs on the shoes, but disc brake calipers don't need this feature. So when running disc brakes on a drum brake proportioning valve you will be dragging the rear pads. I ran one like this for awhile and it works but I warped the rotors pretty quick, not to mention fuel economy wasn't the greatest...

 

[BNielsen]

Another thing to not is if you're switching to rear discs from drums then I think you'll need a different brake proportioning valve. Drum brakes require a 10psi check valve to keep the wheel cylinders from retracting with the force of the springs on the shoes, but disc brake calipers don't need this feature. So when running disc brakes on a drum brake proportioning valve you will be dragging the rear pads. I ran one like this for awhile and it works but I warped the rotors pretty quick, not to mention fuel economy wasn't the greatest...

Already accounted for that, I'll essentially be swapping to a full GMT800 brake system; the hydroboost will get the later style outer half so the 99-07 master cylinder will bolt up, I've got NBS knuckles waiting for a trip to the machine shop to be reamed for the GMT400 balljoint, after that it's all bolt on components.

Brake drag has been a major worry to me when it comes to swaps like this, I know most people say "just delete the ABS" but it's working flawless (knock on wood) in both of my trucks.
With the GMT800 hydroboost modded to bolt in my it should in theory already be proportional for the disc set up. At least that's the conclusion I've come too checking over everything available when it comes to rear end swaps/disc conversions on these trucks.