cbolt Posted August 15, 2011 Share Posted August 15, 2011 I am in the process of installing a 2004r in my car. It currently has the original 2.73 non-locking rear and I know I am going to make the swap to the 3.73's, maybe even an Eaton locking setup and new axles if I can afford it. What is everyones opinion on which route I should take, either swap the gears in the current 10 bolt or upgrade to a 12 bolt. Now before everyone says "12 BOLT!" (I know it's better than the 10 bolt) keep in mind that money is a factor as well as availability of an acceptable donor 12 bolt (I can't find a reasonably priced one anywhere). The car has right at 300hp and I have no plans to race it, simply improve my mph for trips and drive-ability so strength isn't a major issue. Also, will the 3.73's even fit? Thanks in advance. Quote Link to comment Share on other sites More sharing options...
Mike 57 Posted August 16, 2011 Share Posted August 16, 2011 With your power level the 10 bolt will be fine. 3.73 gears are available for most 10 bolts. 3.42s, 3.55s or 3.73s will make it a fun cruiser. Quote Link to comment Share on other sites More sharing options...
cbolt Posted August 16, 2011 Author Share Posted August 16, 2011 So, how does one tell the difference between the 8.2 and the 8.5? I would like to get all my parts ordered unless I have to physically take it apart to measure in which case I won't be able to drive it until the project is done. Quote Link to comment Share on other sites More sharing options...
Mike 57 Posted August 16, 2011 Share Posted August 16, 2011 I am pretty sure that the pinion nut on the 8.2 is 1 1/8 and the 8.5 is 1 1/4 Quote Link to comment Share on other sites More sharing options...
bobsmc Posted August 16, 2011 Share Posted August 16, 2011 I am pretty sure that the pinion nut on the 8.2 is 1 1/8 and the 8.5 is 1 1/4 Â Â ditto! Quote Link to comment Share on other sites More sharing options...
cbolt Posted August 16, 2011 Author Share Posted August 16, 2011 Sounds like some disassembly required to me in order to determine which one I have, correct? Quote Link to comment Share on other sites More sharing options...
Mo's70MCs Posted August 16, 2011 Share Posted August 16, 2011 Sounds like some disassembly required to me in order to determine which one I have, correct? Â maybe not! Â Quote Link to comment Share on other sites More sharing options...
ThirdMC Posted August 16, 2011 Share Posted August 16, 2011 Having the same problem as you cbolt. Can't tell which rear I have. Mine doesn't have the 'lugs' like the 8.5 but also doen't have the cover like the 8.2 in the photo. Can't manage to get a pictiue of mine, or any other photo, to load on the forum either.... Quote Link to comment Share on other sites More sharing options...
Mo's70MCs Posted August 16, 2011 Share Posted August 16, 2011 Having the same problem as you cbolt. Can't tell which rear I have. Mine doesn't have the 'lugs' like the 8.5 but also doen't have the cover like the 8.2 in the photo. Can't manage to get a pictiue of mine, or any other photo, to load on the forum either.... Â maybe 8.2 Â Â Quote Link to comment Share on other sites More sharing options...
Monte7071 Posted August 16, 2011 Share Posted August 16, 2011 That is the BOP 8.2 that came in 70 Monte Carlos but like I said over the years who knows what has been done. Try this site to see if it helps BOP link Here is a pic of a BOP 12 bolt Quote Link to comment Share on other sites More sharing options...
Vaughn Posted August 16, 2011 Share Posted August 16, 2011 Great info Rod!! Quote Link to comment Share on other sites More sharing options...
Monte7071 Posted August 16, 2011 Share Posted August 16, 2011 Here is another site that might help he is a member here he goes by Monzaz. link Quote Link to comment Share on other sites More sharing options...
Vaughn Posted August 16, 2011 Share Posted August 16, 2011 If anyone is looking, Jim (Monzaz) does great work and is reasonably priced. He has done a couple of rear ends for me and I have had zero issues. Quote Link to comment Share on other sites More sharing options...
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