which ones in the order from greatest hp loss to least is it:
12 bolt, 9", and 10 bolt?

 

The Ford 9" will eat up the most and the chevy 10-bolt will eat up the least in almost every case. I made 389rwhp with the stock 10-bolt (4.11 gears) and a 1LE driveshaft. I switched to a Strange 12-bolt (3.73 gears) and a Denny's nitrous driveshaft and lost 26rwhp. A Ford 9" would have lost 30+ rwhp

 

The numbers I've seen published in National Dragster are:

Dana 60: 5% loss
GM 12-bolt: 7% loss
Ford 9-inch: 10% loss

I would expect the 10-bolt to be very similar to the 12-bolt, because it has a similar geometry with respect to pinion shaft offset.

 

Wow, that's pretty sweet. The big debate over the new Dana for the fbodies is the loss. Everyone seems to think it's somewhere between the 12 bolt and the 9". Pretty cool to see that argurably the strongest one is also the most efficient. Now if only they could cut some weight off of it.

 

The loss can be correlated to the offset of the pinion shaft axis from the ring gear centerline. The more offset, the more losses. The Dana has the least offset.

Rotating mass will also be a factor, so the larger diameter gears will add to the losses.