ls1powerz28

I am looking to upgrade my destroyed 10-bolt to a Strange 12-bolt 3.73. How much horsepower to the wheels do you lose by upgrading to a 12-bolt or even a 9 in' ?
Also, does anyone know where to get a cheap strange 12-bolt with 3.73 gears that bolt up directly to my car?

Thanks guys

Injuneer

Since the losses are determined by several factors, there's limited damage when going from the 10-bolt to the 12-bolt. Slightly more mass in the carrier and gears, similar pinion centerline geometry relative to the centerline of the ring gear/axles. I don't know that you would be able to measure the difference, since the pinion centerline appears to be the major factor in mechanical loss.

The numbers I've seen quoted by Evan Smith in National Dragster Tech series are:

Dana 60 (aka Strange S60) = 5%
GM 12-bolt = 7%
Ford 9inch = 10%

The Dana saves HP, but adds about 25# compared to the 12-bolt. The ring gear is larger than the 12-bolt and the 9-inch, so theoretically its a lot stronger than both. Its probably the best choice in the 700-1,000HP range. Above that, the 9-inch offers a lot more options for strength and weight savings. But the 9-inch, with the pinion centerline offset to one side, and 3/4" lower than the 10/12-bolt complicates the torque arm issues and pinion angle issues on the 4th Gen.

The S60 is also slightly less expensive than the 12-bolt, but you are still looking at $2,200 - 2,500.

Moving to "Drivetrain", where a "search" would have uncovered similar discussions.