is a roadmaster sedan rearend the same as a caprice?

i got a posi rearend 3.08 from a 93 Buick road master sedan, will it bolt in a caprice sedan 91-96?

Yes, it will bolt in. In '93 rear gear options were 2.73s, and 3.23s I believe.

oh ok, someone told me the caprice rears and Buick rears were completely different, gears aside

The ones that are different are the ones with disks, and the Caprice units will still bolt up. They just need the disk hardware that is different from the RMS. The Impala rears may be wider. You can measure from axle flange to axle flange to determine if the width is the same. Make sure you either push the axles in, or pull them out until they stop on both so you will be measuring the same thing. The 2.56 gear rears (GM8) have a different offset for the pinion gear, and you can only change ratios if you put a spacer on the ring gear.

mine came from a road master sedan it has drum brakes, my original thought is it should bolt into a caprice sedan but wasent sure at first.

The RMS always has large drum brakes. If you have large drums on the Caprice it will bolt up. If you have small drums on the Caprice, you may need a few parts, but it should bolt in. If the Caprice has small drums you may be getting a larger/heavier duty rear from the RMS.

also this rearend from the Buick road master is posi, g80 to be specific. now is the g80 code posi that i have the same as
a "eaton g80 locker" rearend?

The G80 is a GM OEM posi code, and not an Eaton locker. Since it is a posi, you can probably use any 8.5 inch gears and compatible posi in it.

my stock rearend has 2.23 i believe factory, going from that to 3.08 will i notice a big change on how the car moves?

There is no 2.23, It could be 3.23, so if you are going to a 3.08, you have to either change the gearing in your VSS or change the programming of the computer. If you started with a 3.23, you will feel like your performance has dropped. Check your SPID for the other G codes.

The 9C1 rear is the most narrow, then the Impala SS rear and then the wagon (4" wider than the Impala). Not sure were the Roady sedan falls into the mix.

My rearend is different than yours,.. yours is definitely narrower,.but mine is faster,...

it's hard to tell the difference between 2:93, 3:23's and 3:08's with an lt1 unless you start with 2:56,. then everything seems lighter,.

the second the weather plays nice again im going to take the Buick rearend and have it sand blasted and covered with primer and undercoating to clean it up. re do the seals of course and break lines and connect the brake system

phantom 309 wrote:

My rearend is different than yours,.. yours is definitely narrower,.but mine is faster,...

it's hard to tell the difference between 2:93, 3:23's and 3:08's with an lt1 unless you start with 2:56,.  then everything seems lighter,.

Your rearend is different from everyone elses because your head is stuck up there Nick!
Just couldnt resist,here comes the sh**storm but I was just kidding!

Flash, you have insight.

did road masters ever have 7.5 rearends or were they all 8.5 in 91 to 96 model years. my 308 posi is from a
92 or 93 road master.

All were 8.5s