Sources for GM 12 bolt complete rear ends?

[67King]

Other than Moser and Currie, anyone know of any sources? Those are about $4500. I can get a pretty well built 9" (same diff, ratio, brakes, and upgraded aluminum housing) for about $3100 from Quick Performance. But I'm reading a lot about gear whine on the 9" rears. Current 8.2" is from a later car, and too wide for the wheels I bought (not to mention they are inherently weak!).

[JustJohn]

You might be able to use an Impala 12 bolt. Wider than the Camaro/Chevelle/Nova versions.

OE ones are still hard to find.

[67King]

You might be able to use an Impala 12 bolt. Wider than the Camaro/Chevelle/Nova versions.

OE ones are still hard to find.

I think they'll be too wide. I believe the 67-69 Camaros are the same width as the 64-67 Chevelles. That's what I need. But......what I read online and what I"ve seen are not really consistent, albeit I'm comparing BOP to Chevy. My current one is 61.5" wide, and I need narrower. I *THINK* the early ones are 60" wide, which would be about perfect. I'mgoing to be running coil-overs, so I don't need the spring perch. But I do need the control arm mounts, so if I get the Camaro one, I'll have to do some work to it, and hope I don't end up warping the tubes.

I wasn't sure if there were any sort of aftermarket for new/refurb ones like there is for the Ford 9" ones. Hoping there is.

[dontlifttoshift]

Typically the Strange S60 is the most cost efficient way out.

Make sure the the coilovers you are buying can accommodate the aftermarket shock/control arm brackets regardless of what rear end you go with. Strange, quick, Moser, all have their own idea of what that bracket looks like.

[badazz81z28]

I’m told if you get the prepped/treated gears the 9” will be quieter. Gear FX has some good info on their site. However if the 9” is cheaper than the 12 bolt, the 3rd member probably doesn’t have Best parts. A moser 3rd member with all the upgrades components is $1800 alone. A lot of 3rd members don’t come with 1350 yokes, Daytona pinion supports, nodular iron cases etc. My powder coated housing was over a grand. The axles another $500, brakes $1500. I easily have $4500 into it.

[67King]

I’m told if you get the prepped/treated gears the 9” will be quieter. Gear FX has some good info on their site. However if the 9” is cheaper than the 12 bolt, the 3rd member probably doesn’t have Best parts. A moser 3rd member with all the upgrades components is $1800 alone. A lot of 3rd members don’t come with 1350 yokes, Daytona pinion supports, nodular iron cases etc. My powder coated housing was over a grand. The axles another $500, brakes $1500. I easily have $4500 into it.

A Currie 12 bolt is about $4500. A Quick Performance 9", which uses a rebuilt housing, is a bit over $3000 with an upgraded Yukon aluminum housing. A Moser would be $200 more. Both have Tru Trac diffs.

[JustJohn]

It's anecdotal since I only have the one data point but I have a Moser 12 bolt and was on the fence about gear ratios. I was advised to go with the 3.42 because they were quieter and I have no discernible noise at all from it after 2000 miles.

[67King]

It's anecdotal since I only have the one data point but I have a Moser 12 bolt and was on the fence about gear ratios. I was advised to go with the 3.42 because they were quieter and I have no discernible noise at all from it after 2000 miles.

I'm inclined to think that the noise on the 9" is because the offset/hypoid angle is much greater than other diffs. The tooth count in the pinion probably also affects it. I'd be looking at a 3.70 or 3.73. Again the Ford is likely noisier, 10 teeth to 11.

[andrewb70]

Typically the Strange S60 is the most cost efficient way out.

Make sure the the coilovers you are buying can accommodate the aftermarket shock/control arm brackets regardless of what rear end you go with. Strange, quick, Moser, all have their own idea of what that bracket looks like.

Also, if OEM Dana gears are used, this would be the quietest setup.

Andrew

- - - Updated - - -


I'm inclined to think that the noise on the 9" is because the offset/hypoid angle is much greater than other diffs. The tooth count in the pinion probably also affects it. I'd be looking at a 3.70 or 3.73. Again the Ford is likely noisier, 10 teeth to 11.


The 9" in my Cougar has stock 4.33 gears and it is dead quiet.

Andrew

[raustinss]

Fyi any welding on the axle tubes has a good chance of distorting or warping the tubes . That's being said it is easy to straighten them with equal thermal input 180 degrees from said point . We heat straighten stuff all the time at work , part of being a fabricator . Do what you need to do once you find a housing then take it to someone who can straighten the tubes . I have 3 random tig welds on one of my tubes . The shop I used (when I was 18) chose tig weld to shrink the tube into alignment, said it was way more precise over using a torch .
Good luck

[shelteredchevelle]

I had Spraker Racing do a 12 bolt- narrowed to my dimensions, big ends, 30 spline axles, powder coated, 3.73 gears Eaton posi 3,200.00
Nice piece, runs good and quiet

[Decline]

Quick built my third member with strange hd aluminum housing motive 3.23 gears and tru trac. Very quiet. Gear whine has a lot to do with how it’s put together. I have it loaded in a speedway engineering full floating housing. Moser makes a circle trac 9” floater for like $900. JD man has it under his Camaro I believe. Floating axle rear ends cannot be beat for safety and performance.

[67King]

I had Spraker Racing do a 12 bolt- narrowed to my dimensions, big ends, 30 spline axles, powder coated, 3.73 gears Eaton posi 3,200.00
Nice piece, runs good and quiet

Just heard back from them. Thanks for the heads-up! Likely going to give them a call in a little bit. Price point is a little higher than the Quick 9", but I think this will be my best option.