12 bolt vs Dana 60

[Myron Piatek]

If you're still wanting to try the 12 bolt, perhaps Charlie Boyles could offer some advice and what to expect with a 12 bolt.

http://www.competitionplus.com/drag-...a-legend-lives

[Dwight Southerland]

Hypoid angle for a Dana 60 is less than a 12 bolt. Several years ago, Car Craft did a side-by-side comparison of a 12-bolt, a Dana 60 and a 9-inch. The 9-inch was the loser. No clear winner between the 12-bolt and the Dana.

[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

[Ed McLawhorn Jr.]

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]

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]

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]

9 inch Fords in Chevy new Mopar and Fords