12 bolt vs Dana 60

[GTX JOHN]

We have replaced most of our 8 3/4 mopar rears with Dana 60 AND lost no ET whatsoever on our Stock and SS stuff.

[Ed McLawhorn Jr.]

Originally Posted by GTX JOHN

We have replaced most of our 8 3/4 mopar rears with Dana 60 AND lost no ET whatsoever on our Stock and SS stuff.

John, my main reason for exploring changing to 12-bolt would be the weight difference. Any performance would be gravy. Where I'm at now, I'm stuck with one class and have little to no flexibility to move up a class unless I want to run over 90lbs heavy. There's 116lbs difference to move up one class.

[Rory McNeil]

Originally Posted by Jeff Stout

12 bolt with aftermarket goods will hold up. I'm 3360 10 flat ET with trans brake and around 170 passes. No noise yet. Did break a 4.56 street gear. Went pro gear and that's been it. Also used 4.10 gear with 9 tooth pinion and no problem. If I remember I think 85 lbs lighter then dana

Jeff, was that weight difference with a limited slip diff, or a spool? Over 20 ears ago, when I switched my bracket car from an automatic to a Jerico 4 speed, I decided the old rearend needed updating. I had been using a Ford 9" with 33 spline Strange spool and axles, with a production Ford Nodular iron case, and an unbraced early style housing. After some research, I came to the conclusion that bracing the existing housing, buying an aftermarket case and bigger axles and spool would be comparable to scratch building a Dana 60. So I sold the old 9", and my buddy built a new Dana 60, using a thick tube (heavy) truck housing, billet caps, 35 spline spool & axles, and a T/A load bolt cover. Having heard all the stories about how heavy a Dana 60 was, I was pleasantly suprised when I weighed both rearends. Using the same model brakes, the Dana was a mere 6 pounds heavier than the 9". Now, keep in mind, the Dana had thicker, heavier axles, and was a thick tubed truck housing, while the 9" had a light, early housing and smaller 33 spline guts. I think the move to 35 spline axles in the 9", plus a braced housing would eliminate that 6 pounds. And if I bought an aftermarket iron case, be heavier. Now, I know an aluminum case would make the 9" that much lighter, but again, if I used a thin tube Dana housing, the Dana would also loose some weight. A Dana clutch style limited slip is a huge, heavy unit, replacing that with a spool drops a lot of weight. I can say, after 20+ years of 6000+ RPM clutch dumps, the Dana has been as reliable as an anvil. I have 3 sets of Pro gears of various ratios, and each set has at least 7 years on them, and they all still look great. Only strikes against a Dana that I see, is not as many ratios available as a Ford 9", but the 12 bolt is in a similar situation there as well. Plus the Dana is not as easy to change gears, as throwing another chunk in a 9", but again, same story with the 12 bolt. For my purpose the Dana is a great choice.

[Jeff Stout]

Originally Posted by Rory McNeil

Jeff, was that weight difference with a limited slip diff, or a spool? Over 20 ears ago, when I switched my bracket car from an automatic to a Jerico 4 speed, I decided the old rearend needed updating. I had been using a Ford 9" with 33 spline Strange spool and axles, with a production Ford Nodular iron case, and an unbraced early style housing. After some research, I came to the conclusion that bracing the existing housing, buying an aftermarket case and bigger axles and spool would be comparable to scratch building a Dana 60. So I sold the old 9", and my buddy built a new Dana 60, using a thick tube (heavy) truck housing, billet caps, 35 spline spool & axles, and a T/A load bolt cover. Having heard all the stories about how heavy a Dana 60 was, I was pleasantly suprised when I weighed both rearends. Using the same model brakes, the Dana was a mere 6 pounds heavier than the 9". Now, keep in mind, the Dana had thicker, heavier axles, and was a thick tubed truck housing, while the 9" had a light, early housing and smaller 33 spline guts. I think the move to 35 spline axles in the 9", plus a braced housing would eliminate that 6 pounds. And if I bought an aftermarket iron case, be heavier. Now, I know an aluminum case would make the 9" that much lighter, but again, if I used a thin tube Dana housing, the Dana would also loose some weight. A Dana clutch style limited slip is a huge, heavy unit, replacing that with a spool drops a lot of weight. I can say, after 20+ years of 6000+ RPM clutch dumps, the Dana has been as reliable as an anvil. I have 3 sets of Pro gears of various ratios, and each set has at least 7 years on them, and they all still look great. Only strikes against a Dana that I see, is not as many ratios available as a Ford 9", but the 12 bolt is in a similar situation there as well. Plus the Dana is not as easy to change gears, as throwing another chunk in a 9", but again, same story with the 12 bolt. For my purpose the Dana is a great choice.

With a steel spool, 33 spline axles, aluminum cast cover with bolts to keep caps in place. Might get in trouble with thin tube housings. I did bend 1 12 bolt housing with no HP stick car that weighed 3775

[Ed McLawhorn Jr.]

Originally Posted by Jeff Stout

12 bolt with aftermarket goods will hold up. I'm 3360 10 flat ET with trans brake and around 170 passes. No noise yet. Did break a 4.56 street gear. Went pro gear and that's been it. Also used 4.10 gear with 9 tooth pinion and no problem. If I remember I think 85 lbs lighter then dana

Jeff, the only difference in car now and when dad ran it is the truck Dana with thick tubes and a coilover shock replacement. Car with no driver is right at 95lbs heavier now. I found some old weight numbers, so your 85 lbs might be close.

[Mike Pearson]

Originally Posted by Ed McLawhorn Jr.

Been thinking about taking very heavy dana out and replacing with 12 bolt. Its known the Dana is bullet proof and takes more energy to rotate than 12 bolt. Car is a 283 ss/gt auto in 3430lb wagon with a 6:20 gear and 30" radial tire. There was a 12 bolt with 6:14 and 28.5" bias tire dad ran in the car in the 80's before rules changed on heads. Besides more hp to run dana, I'm looking at the difference in weight. With dana, I'm pretty much locked into one gt class due to not getting light enough. Would the oem 12 bolt hold up or do I need to think more about an aftermarket housing and is a good 6:14 still available? Thanks.

With good parts you should be able to get a couple of seasons on.a R&P. One of my friends ran a 12 bolt in his GT car. 350 295/313 combo at 3100 and would get 2 seasons on a 5.96.