ejw71 Posted October 12, 2003 Share Posted October 12, 2003 What are the gear diameters (both 8.5"?) for 10 bolt and 12 bolt rear ends? Is the 12 bolt stronger because the components are larger? Thanks, Ed ------------------ '71 Black 406/700R4/10bolt, Branson participant '71 Sandalwood SS454 '71 Project Darkest of Dark Green Metallics/GenIII346LS1/4L65E/12bolt posi Link to comment Share on other sites More sharing options...
wallaby Posted October 13, 2003 Share Posted October 13, 2003 And it's held together with more bolts. Link to comment Share on other sites More sharing options...
alex's72fgmc Posted October 13, 2003 Share Posted October 13, 2003 8.5 and 8.2 ring gear sizes are the two sizes for 10 and 12 bolt 12 bolt is stronger than the 10 bolt but a 14 bolt out of a 1/2 ton pickup gmc/chevy z-71 k-1500 series is very nice and strong.... "been debating putting it in the monte with it narrowed and converted over.... alex [This message has been edited by alex's72fgmc (edited 10-13-2003).] Link to comment Share on other sites More sharing options...
David Mau Posted October 14, 2003 Share Posted October 14, 2003 Ed, In the current issue of "Muscle Car Review" (Fall 2003, which has the blue '69 "2 Fast 2 Furious Yenko Camaro on it) there's an article about strengthening rearends. It starts on page 70 and is titled "100 Percent Chevy". It primarily covers 12-bolt rearend performance upgrades by Currie Enterprises. In the text it states: "Why the name? Technically, it is the number of bolts that hold the 8.875-inch od ring gear to the differential. Urban legend incorrectly said it was because of the 12 bolts holding the rear cover on. Twelve-bolt rearends were produced from '64 to '72. They are found in '64-'72 Chevelle A-bodies, '67-'72 Camaro/Firebird F-bodies, '66-'70 Chevy II/Novas, and '70-'72 GTOs. They were also installed in '65-'70 Chevrolet fullsize B-bodies and '70-'72 Monte Carlos. Within the car lines, a 12-bolt would be found with a high-output small-block and all big-block applications." I don't see where it specifically says why the 12-bolt is stronger than a 10-bolt, but it does state that "...the bottom line is that it is a solid design and very stout" when talking about the 12-bolt rearend. It also goes on to say "Starting in '71, GM began installing the 10-bolt rearend, which had an 8.500-inch ring-gear diameter." Great issue of the magazine. You might want to check it out. Dave ------------------ I'm Just Enjoyin' That Great S-S-Sensation; Diggin' My First G-G-Generation. Link to comment Share on other sites More sharing options...
ejw71 Posted October 22, 2003 Author Share Posted October 22, 2003 Thanks Dave. Thought "Muscle Car Review" was purchased by "Hot Rod" and therefore out of publication. It has been my understanding that some 12 bolt cover rear ends have 10 bolt guts. Ed Link to comment Share on other sites More sharing options...
David Mau Posted October 22, 2003 Share Posted October 22, 2003 You're welcome, Ed. Yeah, I'm with you in thinking that "Muscle Car Review" had been out of publication for a while. This latest one states with the publishing info that it is a publication of "Chevy High Performance". As far as some 12-bolt-covered rearends having 10-bolt guts... Hmmmmm, I can't answer that one. Sorry. Dave ------------------ I'm Just Enjoyin' That Great S-S-Sensation; Diggin' My First G-G-Generation. Link to comment Share on other sites More sharing options...
Grease Posted October 23, 2003 Share Posted October 23, 2003 Dave i think that 10bolt/12bolt axle is a BPO axle . i cant remember if its a 10 bolt cover on a 12 bolt carrier or the other way around.its been briefly discussed a good while back . mike Link to comment Share on other sites More sharing options...
Andreas Posted October 23, 2003 Share Posted October 23, 2003 Quote: Originally posted by David Mau:Yeah, I'm with you in thinking that "Muscle Car Review" had been out of publication for a while. Nope, I bought a "Fall 2003" issue just two weeks ago. It is now published quarterly... ------------------ 71 Monte 454 HO 5- Speed "FULMNTE" 01 Camaro V6Andreas' Monte Carlo Site Member NMCOA, FGMCC (Event Coordinator) ------------------------------------------ ------------------------------------------ "It ain't a car if it's not a Monte" Link to comment Share on other sites More sharing options...
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