[Malibu73]

Okay so I'm looking at this 12 bolt 4.11 posi that's for sale that this guy took out of a '71 chevrolet Malibu. It has Ring=8.875" Pinion=1.625" Bolts=12 Spline=30.

I have a '73 Chevrolet Malibu with the stock 2.73 rear end which I think is a 10 bolt either 8.2" or 8.5", I'm not sure....

I really would like that 4.11 because my car weighs in at almost 2.5 tons with me in it, it's a sedan with a mildly aggressive 350 that my dad and I built in it.

It's also got a 700R4 tranny so it cruises at REAL low RPM's on the highway. I was thinking a set of 4.11's would go great with that 700R4 because the 4th gear would allow me to still cruise at reasonable RPM's on the highway but my acceleration would increase dramatically.

The thing is, the 4.11 is out of a 12 bolt rear end, it's just the gears, not the whole rear. I was wondering if I could just shove that in my rear end without any trouble, or if it would be totally incompatible.

Could you help me out here? Thanks.

[Guy Hiltz]

No ,the gears will not interchange from the 12 to the 10 bolt.

[Hippie]

As stated above the 12 bolt gears won't fit. FYI, your '73 has the 8.5" Corporate 10-Bolt, it is plenty strong. Posi's and gears are fairly easy to find, if you buy a new set 4.11's are about the cheapest ratio there is for the 8.5". I'd stick with 3.73's myself but that's just me. The factory 2.73 and lower (higher numerically) carriers can take the 4.11 without a spacer or special ring gear. Any '73-'88 28 spline 8.5" posi will swap into your axle housing. The '71-up Camaro, Firebird and Nova also carried 8.5" rearends and some of the B-O-P A-bodies as well.