Rear Diff


#1

I have a 1979 Chevrolet Monte Carlo with a 7.5" 10bolt that had a 41 ring gear and a 18 pinion. I have run into a big problem with this diff. It just so happened to grenade while driving and I just got the engine and tranny complete.



Now on to my question is there a way to beef up this differential or is there like a 8.2 or 8.5 that will bolt in with little work???


#2

Oh and this is a bit more then the little 267 120hp v-8, it now like a 400+ hp 355, running through a TH350 trans with the B&M transpack, TCI sizzler converter, and true dual exhaust with headers.


#3

It sounds like you need to at least upgrade to the 8.5in 10 bolt rear. GM used these in pickup and some of the older cars, but I’m not sure which ones. The best bet would probably be the 8.875in 12 bolt rear. Not as easy to find, but will be a little stronger than the 8.5in.

I regularly see 10 and 12 bolt rears on ebay.


#4

i agree with this guy


#5

You might be able to find a Ford 9" rear end, they seem to be pretty popular, even with the Chevy guys


#6

I not a big fan of intermingling GM and the other 4 letter word, I do understand that a lot of people do that just because it is a strong diff but I like keeping it in the issue with cars in the family. I am thinking of getting a 8.5 which is fairly stout only .375 smaller then a 12 bolt and I know that I can order a 12 bolt from moser for about 2400 but I am a man with a budget and I don’t currently have all the fab tools do just grab any diff and make it work. What I really need to do is find one (8.2 or 8.5) that will bolt in with little mods maybe tweaking the trailing arms a bit. But I don’t know what late 70’s thru mid 80’s cars may have came with that type of differential to really look for. I apprecaite all the info and input that I get so please don’t take offense on this.


#7

The problem is I think this model Monte has a four-link rear end. Any replacement rear diff would need to have the same four-link attachment points to bolt in. If this is the case, you’ll need to ask at some customizing/hot rodding/ drag racing sites to find a 10-bolt or 12-bolt replacement options that also have four-link brackets on the axles.

BTW, I did see on the ‘Muscle Car’ show on SpikeTV that they replaced a weak rear axle in a sooped-up El Camino with a Ford 9-in, but had to fab up and weld on the four-link brackets to make it work. Of course, you should see the shop these guys have to work with.


#8

I’ve seen that show and I watch the whole power block every Sunday from 8am to noon. It’s my day off so I relax. They do do some awesome stuff though.