9 Inch Ford, Dana 60 or 12 Bolt

[77ta]

I some point in my cars evolution I think I will need to upgrade the 8.5 10 bolt. I broke the gears once and rebuilt it and the car will probably not get slower. The intent is a do it all well, handling, braking, drag strip, and cruising... I am working on the handeling and comfort parts now. I don't know what I'll do later on power wise but I want to be prepared for anything so lets say must support 800+ rwhp to be safe... it may make 450-500 rwhp now.


Some day I wish to do a little road course and more Autocross racing. I am looking for the best options for strenght, and handeling mainly. I have read the 12 bolt is the most efficient of the 3 so that is a question to I guess... What about differential options etc...
The car is heavy about 3900 with driver.

Thanks

[big gear head]

The 12 bolt is plenty good for what you have right now. It is also lighter and uses less power than the others. My second choice would be the Dana 60. Both of these are going to be much cheaper than the 9 inch and they are both lighter and use less power. The Dana is stronger than the 12 bolt and will handle more than 800 HP. The 12 bolt might be colse to it's limit at that level, although the Moser 12 bolt is much stronger than the original Chevy 12 bolt.

[rixtrix1]

One of the car mags did a chassis dyno test on the rears mentioned in you post, and the difference in efficiency was almost negligible.IIRC it was 5-6hp; 12 bolt, then 9" and D-60 last( least efficient and heaviest, but only 10-12# more. If you plan to build it and forget it, then do the 12 bolt or Dana 60. If changes are in order, i.e. drag gears vs. roadrace, then do the 9" for ease of gear changes. I'd stay away from the cone type diffs, regardless of their advertising superior torque holding ability. Detroit lockers are bulletproof, but noisy, gear types look good but I've heard they don't last with big HP. Personally, I like the Eaton clutch style with Kevlar clutches. Another thing is if you're building it yourself, or buying a complete unit ready to bolt in. A 9" is the easiest to set up, IMO. Best to do some research and make some calls to the various axle mfg and tell them what you're looking for in terms of performance.

Ric