Diff housing swap

[drewcrew]

I've got a 1991 Chev rcsb 2-wheel drive. I'm looking for a housing that will be 2"" narrower per side. Maybe one out of a 454 SS pick-up ? Or maybe a 4-wheel drive ? I'd like to pull mine out and bolt the other one in without a lot of cutting, welding and fab work. I know this is a long shot but I was hoping somebody on here would know.

 

[someotherguy]

The SS uses a 9.5" 14 bolt but with the small brakes instead of the bigger ones used on the C2500LD's. They're not any narrower than your existing 10 bolt.

The rear ends used in 4x4's are actually wider, so that's going the wrong direction.

You'll either need to adapt something from a completely different application, or chop yours.

Richard

 

[drewcrew]

The SS uses a 9.5" 14 bolt but with the small brakes instead of the bigger ones used on the C2500LD's. They're not any narrower than your existing 10 bolt.

The rear ends used in 4x4's are actually wider, so that's going the wrong direction.

You'll either need to adapt something from a completely different application, or chop yours.
That's pretty much what I thought. I didn't expect it to be easy. That's why I posted it here because if there was something I could do I would get the straight scoop. I thought maybe a 1/2 ton van might be different than mine. The only reason I want to do this is to fit a set of American Racing Torque Thrust's on it. The 8" (or 8 1/2") have a 3 3/4" backspace and that's not enough backspace for the tires I'm using. Their BFG's 285x70x15 and there is just enough room on the wheels I'm running now and they have a 5" backspace. I've got about 2" of clearance on the back side now. Thanks a lot for getting back to me Richard. I was hoping you would see my post.

 

[bluedevil]

Its minor trimming, and weld on perches, but b-body impala / caprice is 1.5" narrower per side...you'd get a disk upgrade and most likely posi too.

 

[drewcrew]

Its minor trimming, and weld on perches, but b-body impala / caprice is 1.5" narrower per side...you'd get a disk upgrade and most likely posi too.

Thanks for the idea Bluedevil. Do you know what years would work ? I checked the American Racing website again and they have a 15x8 with 4 1/2 backspace that would get the job done. The only problem is they have a 4 3/4" bolt circle. Changing the bolt circle is the easiest way to go but your idea would give me 4 wheel discs and maybe posi. I'll have to drink another pot of coffee and do some more measuring. Thanks again for the info and if you would tell me what years I can use I'd really appreciate it. I knew posting my question on here would give me the info I needed.

 

[sewlow]

If you go looking for an Impala rear diff., the sedans with posi use an Eaton LSD. Look for the oblong alu. tab that says, 'Posi-lube ONLY', attached to one of the cover bolts.
The wagons use a Gov-bomb. Avoid those! If you're going through the trouble of doing this, why use a carrier that is known to be problematic?
SS's, & the 9C1's, come with the discs, but the hard line hose ends have to be changed to fit the discs. You'll need lines with GMT400 ends where the hard lines hook to the soft line & the Impala ends at the other.

 

[drewcrew]

If you go looking for an Impala rear diff., the sedans with posi use an Eaton LSD. Look for the oblong alu. tab that says, 'Posi-lube ONLY', attached to one of the cover bolts.
The wagons use a Gov-bomb. Avoid those! If you're going through the trouble of doing this, why use a carrier that is known to be problematic?
SS's, & the 9C1's, come with the discs, but the hard line hose ends have to be changed to fit the discs. You'll need lines with GMT400 ends where the hard lines hook to the soft line & the Impala ends at the other.

Thanks for posting this info sewlow. I know somebody that has a complete diff out of a wagon. I don't think his has discs on it but I could be wrong.

 

[sewlow]

NP!
IIRC, the wagons didn't come with the discs. And...it seems to me that the wagon diffs are wider than the sedans, & came equipped with stupid gear ratios. Anything from 3.08 to 2.7something!
It's been a while since I researched this, but I found a lotta info on the Impala rear ends on an Impala SS forum.
Just can't remember which one! I had saved a bunch of that on my old computer, which then had a mental melt-down!
Someone there had posted up a chart of all the differences with gear ratios, widths & disc applications.