12 bolt vs Dana 60 - Page 3

ImBack · 07-28-2020, 10:56 PM

My cousin has a '71 Chevelle it's a bracket car, weighs 2920 with a 555 CI,runs 550s in the eighth mile with a 12 bolt. He was only getting about a hundred runs out of a ring and pinion but switched to a 488 I believe has a larger pinion? It has a t a girdle on it and good axles and spool but it's nothing special.

Ed McLawhorn Jr. · 07-29-2020, 10:11 PM

Quote:

Originally Posted by Tom Meyer

I have run a 12 bolt in my Chevy II forever, steel spool reg axles 6.14 gear. 283 SS car with brake 6000 + . Used good gear oil and had very few problems putting hundreds of runs on the gears. Only if I was looking for saving weight would I switch. There is a difference in sprung and unsprung weight that may pick the car up. Unless you get the 12 bolt stuff cheep money might be better on other go fast parts. Way back in the day Rick Johnson ran a 12 bolt in his hemi car. Tom

Hey Tom. Good to hear from you! Primary reason would be weight, if any performance it would be gravy. While I have no prob with the 14.00 break in GT class. I can't get light enough for the 13.50 break GT class. I had forgotten Rick had one in is hemi. I do need to call you soon and discuss something though.

Tom Goldman · 07-30-2020, 11:15 AM

Since I have parts for both 12 bolt and Dana 60 in the shop right now ,I decided it was time to weigh in ,literally by putting everything on the scale.
Both rears measured within an inch of each other ,12 bolt 53" ,Dana 54" both have 1/4" chrome moly tubes and 3.15"bearing ends, both have steel caps.
Dana 60 90 pounds ,
12 bolt GM 70 pounds
Both have Strange light weight steel spools
Dana 60 13 pounds
12 bolt GM 8 pounds
Both have standard non lightened gears
Dana 60 16 1/2 pounds
12 bolt GM 14 pounds
Axles and bearings and yokes are within ounces
So the total unsprung weight difference is 27 1/2 pounds and rotating weight difference is 7 1/5 pounds.
The Dana still is better for frictional loss efficiency than the 12 bolt but that surely is offset by the difference in rotating mass.
Bottom line is both have their strengths and weaknesses . Ratio choice is much better for the 12 bolt for sure , and if we are talking a Stocker ,well you know what you
have to do .

MRE 7171 · 07-30-2020, 04:42 PM

Question, what does a COPO, Cobra Jet and Drag Pack cars have for rear ends and what gear ratio and tire size? Thanks

Ralph A Powell · 07-30-2020, 07:44 PM

9 inch Fords in Chevy new Mopar and Fords

MRE 7171 · 07-31-2020, 08:23 PM

What gear ratio and tire size on those different manufactures

07-28-2020, 10:56 PM	#21
ImBack Junior Member Join Date: Jan 2020 Posts: 27 Likes: 0 Liked 5 Times in 4 Posts	Re: 12 bolt vs Dana 60 My cousin has a '71 Chevelle it's a bracket car, weighs 2920 with a 555 CI,runs 550s in the eighth mile with a 12 bolt. He was only getting about a hundred runs out of a ring and pinion but switched to a 488 I believe has a larger pinion? It has a t a girdle on it and good axles and spool but it's nothing special.

07-30-2020, 11:15 AM	#23
Tom Goldman VIP Member Join Date: Jan 2003 Location: Allentown,PA Posts: 2,474 Likes: 885 Liked 858 Times in 234 Posts	Re: 12 bolt vs Dana 60 Since I have parts for both 12 bolt and Dana 60 in the shop right now ,I decided it was time to weigh in ,literally by putting everything on the scale. Both rears measured within an inch of each other ,12 bolt 53" ,Dana 54" both have 1/4" chrome moly tubes and 3.15"bearing ends, both have steel caps. Dana 60 90 pounds , 12 bolt GM 70 pounds Both have Strange light weight steel spools Dana 60 13 pounds 12 bolt GM 8 pounds Both have standard non lightened gears Dana 60 16 1/2 pounds 12 bolt GM 14 pounds Axles and bearings and yokes are within ounces So the total unsprung weight difference is 27 1/2 pounds and rotating weight difference is 7 1/5 pounds. The Dana still is better for frictional loss efficiency than the 12 bolt but that surely is offset by the difference in rotating mass. Bottom line is both have their strengths and weaknesses . Ratio choice is much better for the 12 bolt for sure , and if we are talking a Stocker ,well you know what you have to do . __________________ Tom Goldman 1500 SG , 1506 STK Last edited by Tom Goldman; 07-30-2020 at 11:18 AM.

07-30-2020, 04:42 PM	#24
MRE 7171 Junior Member Join Date: Sep 2018 Posts: 58 Likes: 41 Liked 95 Times in 24 Posts	Re: 12 bolt vs Dana 60 Question, what does a COPO, Cobra Jet and Drag Pack cars have for rear ends and what gear ratio and tire size? Thanks

07-30-2020, 07:44 PM	#25
Ralph A Powell Member Join Date: Oct 2017 Location: Bay City Texas Posts: 387 Likes: 2 Liked 225 Times in 136 Posts	Re: 12 bolt vs Dana 60 9 inch Fords in Chevy new Mopar and Fords

07-31-2020, 08:23 PM	#26
MRE 7171 Junior Member Join Date: Sep 2018 Posts: 58 Likes: 41 Liked 95 Times in 24 Posts	Re: 12 bolt vs Dana 60 What gear ratio and tire size on those different manufactures