A: 2.87 is the break. 2.72 and 2.56 are on the same carrier. From: TABunsey@xxxxxxx Subject: Re: Axle and gear ratio interchange confusion To: mail@xxxxxxxxxxxx Message-ID: <ADVANCES62xzCnldxmr000014fb@xxxxxxxxxxxxxxxxxxxxxxx> Marty: There is no error in your logic. 2.87 gears WILL fit anyplace that a 3.54 gear will fit. The eBay vendors are UNINFORMED and INCORRECT. There is no difference (at least with Stock AMC gears). AMC ONLY MADE ONE CARRIER ASSEMBLY FOR THE MODEL 20 REAR AXLE (Well, actually there are two carriers--a "Twin Grip" carrier and an "Open" carrier). LOOK IN THE AMC PARTS BOOK. ONLY ONE PART NUMBER!!!!!! The aftermarket idiots keep saying that there is a "break" around 3.07 ratio, or so. IT AIN'T SO (AT LEAST AMC DOESN'T THINK SO). I have pulled 3.54 gears and replaced them with 2.87 gears IN THE SAME HOUSING, SAME CARRIER. IT BOLTED TOGETHER AND WORKED FINE. FOR YEARS!!! Behind a 401. Alright, alright. Yes, AMC DID use a different carrier for the Concord/Pacer V8 cars with the 2.56 ratio. But this only applies to 1978-79 model year cars with an automatic and no "Twin Grip". I have such a ratio I took from a V8 Pacer. I installed it in a V8 Rambler American rear axle. Works fine, too. Bolts right in as an assembly. The AMC 6-cylinder rear end DOES require one of two carriers, and the change IS around 3.08. It looks as if the taller ratios have a pinnion gear with such a large diameter that the mounting flange on the carrier had to be moved outboard to keep proper gear mesh. If I sound "touchy" about this, it's because I am. Every couple of months the same issue raises it's ugly head. Then it gets talked to death & resolved. Then a few months go bye, and the issue comes up again. Arghhhh!!!!! Boy, it would be nice if the list would permit "bold face", "underlines" and "italics" to emphasize various points. But since it doesn't, I need to use CAPS instead. Tom Bunsey My "bible" is the AMC Parts Books. After all, AMC built the cars, Not some aftermarket guys who think if it works that way on "Chebbys", it must work that way on everything else.