etel64 10 Report post Posted November 11, 2012 This is the rear in my 69 Mach. I dont think this is the original. I know its an open rear and am interested in making it a Traction lok. Can I buy the center section if it is a 8, 8.8, 9" rear? Quote Share this post Link to post Share on other sites
maxum96 32 Report post Posted November 12, 2012 (edited) It's an 8". If your car is an original Mach1, someone took the original 9" rearend out and put that 8" in. Mustangs with 351 or larger engines came factory with a 9" rearend. Boss 302 and 65-66 Shelby Mustangs were the exception to that rule. Edited November 12, 2012 by maxum96 Quote Share this post Link to post Share on other sites
JTG 10 Report post Posted November 12, 2012 I thought stock Mach I cars with a 351 2V came with an open 8" rear? Quote Share this post Link to post Share on other sites
maxum96 32 Report post Posted November 12, 2012 I thought stock Mach I cars with a 351 2V came with an open 8" rear? My car was an H code (351w 2V) car from the factory. Mine came with a 9" rearend. Quote Share this post Link to post Share on other sites
Lemon Owner 11 Report post Posted November 12, 2012 my car was an h code (351w 2v) car from the factory. Mine came with a 9" rearend. x 2 Quote Share this post Link to post Share on other sites
rawlinss 14 Report post Posted November 12, 2012 (edited) http://feedback.ebay.com/ws/eBayISAPI.dll?ViewFeedback2&userid=vornhagenmotors&ftab=AllFeedback&rt=nc&myworld=true I was able to convert my 8" rear end to a 3.55 POSI rear end for $650 plus shipping from the contact above.... I saved him as a favorite seller in my ebay account, he doesn't appear to have anything on line currently, but you might be able to contact him) Edited November 12, 2012 by rawlinss Quote Share this post Link to post Share on other sites
TonyV8 10 Report post Posted November 12, 2012 So this is a 9 inch rear end more round than oval? Quote Share this post Link to post Share on other sites
02Lightning 10 Report post Posted November 12, 2012 So this is a 9 inch rear end more round than oval? Yes, another way you can tell from the other side is one of the bottom bolts you can't use a socket on it. You have to use a open or box end wrench on it to get the nut off. On an 8" you can use a socket on all of the nuts. Quote Share this post Link to post Share on other sites
miketyler 15 Report post Posted November 12, 2012 Here's a good page I have bookmarked that explains the variations and differences in 9" rears and some 8" http://www.kevinstang.com/Ninecase.htm Quote Share this post Link to post Share on other sites
LindenBruce 27 Report post Posted November 12, 2012 This is the rear in my 69 Mach. I dont think this is the original. I know its an open rear and am interested in making it a Traction lok. Can I buy the center section if it is a 8, 8.8, 9" rear? For the 8" and 9" the answer in short is yes, you can buy a different center section. The 8.8" is set up more like a GM 10 bolt, the carrier is integral with the housing. Bruce Quote Share this post Link to post Share on other sites
etel64 10 Report post Posted November 16, 2012 Thank you all. that was very helpful. Looks like I should be looking for a 8" locking center section. I want to wear the tires evenly.:cool2:. Would the drive shaft need to be different? are the yokes different? Quote Share this post Link to post Share on other sites
RPM 1,190 Report post Posted November 17, 2012 (edited) The traction loc or Detroit locker has nothing to do with the shaft or yoke. Bad news is that 8"ers are usually more expensive than a 9". Edited November 23, 2012 by RPM Quote Share this post Link to post Share on other sites
cobra3073 24 Report post Posted November 22, 2012 As Maxum 96 noted and/or inferred, ALL 1969 351 (2V and 4V) Mach 1 should have a 9" ring gear set from the factory. Most of them share a 28 spline axles but some might have the 31 spline axles. The 302s would have an 8" or 7 3/4" ring gear but that application was not available for the 1969 Mach 1. I missed it but if you post up your rear end code, we should be able to tell you exactly what your Mustang came with from the factory. Also, as noted, the 8'' stuff might be more expensive to acquire than the 9" but their are "providers." The easiest approach would be to just drop in a complete 9" carrier with the 28 spline as you would not have to change your axles shafts unless you go to 31 or 35 spline. BT Quote Share this post Link to post Share on other sites
maxum96 32 Report post Posted November 23, 2012 (edited) Most of them share a 28 spline axles but some might have the 31 spline axles. The 302s would have an 8" or 7 3/4" ring gear but that application was not available for the 1969 Mach 1. Only the big block cars got 31 spline axles if I'm not mistaken. Possibly Boss 302's did too. Mustangs with 289/302 engines (with the exception of the Boss 302, Shelbys and I've been told K code 289's) all got 8" rearends. 6 cylinder cars got the 7 3/4" ones. Edited November 27, 2012 by maxum96 Quote Share this post Link to post Share on other sites
cobra3073 24 Report post Posted November 23, 2012 Only the big block cars got 31 spline axles if I'm not mistaken. Possibly Boss 302's did too. Mustangs with 289/302 engines (with the exception of the Boss 302 and Shelbys) all got 8" rearends. 6 cylinder cars got the 7 3/4" ones. According to "The Hollander", the 1969 Mustangs with 302 engines could have either the 8" or the 7 3/4" diameter ring gears. It is pretty well accepted that "during the day", Ford routinely utilized "mis-matched" parts on the line, when necessary. I would be curious as to what Members on the Site originally had in their "regular" 1969 302 based Mustangs for ring gears. Hope this is not off topic. BT Quote Share this post Link to post Share on other sites
maxum96 32 Report post Posted November 23, 2012 According to "The Hollander", the 1969 Mustangs with 302 engines could have either the 8" or the 7 3/4" diameter ring gears. It is pretty well accepted that "during the day", Ford routinely utilized "mis-matched" parts on the line, when necessary. Not trying to be argumentative here. But in nearly 30 years of playing with vintage Mustangs and many many hours of junk yard scrounging, I have yet to ever see a factory V8 Mustang with a 7 3/4" rearend. Have you ever seen one? The only ones I've ever seen was where someone swapped a V8 into a 6 cylinder car. Just because it's in the Hollander exchange list doesn't make it so. Quote Share this post Link to post Share on other sites
cobra3073 24 Report post Posted November 23, 2012 Not trying to be argumentative here. But in nearly 30 years of playing with vintage Mustangs and many many hours of junk yard scrounging, I have yet to ever see a factory V8 Mustang with a 7 3/4" rearend. Have you ever seen one? The only ones I've ever seen was where someone swapped a V8 into a 6 cylinder car. Just because it's in the Hollander exchange list doesn't make it so. ...and I ABSOLUTELY believe you as it relates to your inference that "The Hollander" is not necessarily correct. Yes, I too have spent a LOT of time in the junk yards (hence the reference to Hollander) searching for the "gold." I also confess that in my nearly 40 years of swapping out Ford engines, rear ends and transmissions, I have not concentrated on the small block stuff (other than the Clevelands) so I have never even CHECKED a "regular" 302 Mustang rear end. I, too, am not trying to be "argumentative" but was just curious...still am. BT Quote Share this post Link to post Share on other sites
1969vert 55 Report post Posted November 23, 2012 Some of the 250 six cyl came with 8" also ..5 lug.. Quote Share this post Link to post Share on other sites
maxum96 32 Report post Posted November 23, 2012 Some of the 250 six cyl came with 8" also ..5 lug.. That I have seen. I think that was starting in 1969 or 70. But I wouldn't swear to it. Quote Share this post Link to post Share on other sites
etel64 10 Report post Posted November 26, 2012 63C B5 3A 26B 16 6 X BODY CLR TRIM DATE DSO AXLE TRANS Thanks Cobra, I deciphered this as a 3:00 axle. What does one mean by "provider"????? I am hoping to just replace the center section and not the axles. the housing is all done and clean, installed and running. What was with the 7.75 ring confusion ? Is there a 8.75 ring and a 9"? Quote Share this post Link to post Share on other sites
cobra3073 24 Report post Posted November 26, 2012 63C B5 3A 26B 16 6 XBODY CLR TRIM DATE DSO AXLE TRANS Thanks Cobra, I deciphered this as a 3:00 axle. What does one mean by "provider"????? I am hoping to just replace the center section and not the axles. the housing is all done and clean, installed and running. What was with the 7.75 ring confusion ? Is there a 8.75 ring and a 9"? Yes, you are correct in your deciphering of the gear ratio. Provider has to do with the aftermarket companies such as Currie, Strange, etc. Here is a link to a company that carries the 8" carrier (center section) as a complete unit. You should be able to utilize your current housing and axles. http://www.justrearends.com/ Yes, there is an 8" and a 9" rear end. Both 8" and 9" rears could come with the same number of splines on the axles (28) while the 31 spline axles are found only on the 9", per the sources. For the '69 Mustangs, the 9" rear end was generally found on 351, 428 and 429 engines. Generally speaking as it pertains to Mustangs, the 7 3/4" rear end came on those built with the six cylinder engine. Our external discussion on this thread had to do with whether or not some 302 engines (which usually came with an 8") might have come with a 7 3/4" inch ring gear. I am sorry if this somewhat "off-topic" discussion may have caused confusion. BT Quote Share this post Link to post Share on other sites