Like always the "stock" Dana is stronger than a "stock" 9" Now build a 9" without ANY Ford parts then the race is on. Three bearings to support the pinion against the ring gear will ALWAYS be better than two And yes it will cost about twice as much but in the end you will have a better unit. Still have a Dana in my car though
Gus
100% agree
Build one w/ good parts and the 9" is better.
That efficiency argument is a wash. You'll never see it, unless you're in a low powered class car that needs every tiny ounce of free movement to run a number. The benefits of an aftermarket 9" far outweigh any efficiency issue.
This is all true.
I agree but still run a Dana 60. Most of my buddies all have there cars dialed in with 9", so the simplicity of being able to do a quick gear change never matters anyway. They have been running the same gear ratio for years now. The major benefit beside new parts availability is to build a spare center section & to have in the trailer if you break one.
Build one w/ good parts and the 9" is better. 
