Dana 60, or new 3'rd member for my 8-3/4 rear axle ? Where to buy?

[johannes]

Hello friends.
I want to change my rear axle ratio,...and I prefer an easy job.
This means either a new 3'rd member, or a complete rear axle.
My preferred ratio will be 3.23:1 or in that range.
My 'Cuda clone has a Hemi converted 440 (Stage V hemi conversion heads) and a tad of laughing gas.
727 and GV.
No drag racing (as it is a convertible), but I would like to heat the tires from time to time.

From what I gather, a 8-3/4 should be up for the task (It has been for some years at least)
....and I also understand that a Dana 60 comes with 3.54:1.....

With this in mind, do you agree that I stick to my 8-3/4 ?
If so, please recommend supplier for 3'rd member and type of diff brake.

All input welcome,..THANKS !!

[brads70]

If you have a GV then I would go for a higher number for the gear ratio. I wished I had gotten 3:73 instead of 3:55 in the Dana I bought from DrDiff. It all depends on your cam selection though.

[dodj]

I believe the 8 3/4 will be just fine. Not drag racing you will have street tires on your car so the rear will not be 'shocked' hard like it would with sticky slicks on launch.

[anlauto]

Doctor Diff 

[msbaugh]

I agree with brads.... 3.23 is probably a bad call, especially if you have a gear venders in mind and still want to light them up from stoplight to stoplight. I'd say stick with 3.73 or 3.91 if you by from dr. Diff.  Without slicks an 8 3/4 will do fine... You can also collect center chunks like me and swap gears whenever you want

What gears do you have in it currently? What torque converter/stall?  You can't just swap gears with an auto and expect everything to work together right

[msbaugh]

Also, I would love to hear about this hemi head wedge motor you have!!! Have details or pictures??? I've heard of them before, sounds cool!

[Sinatra]

You didn't mention what your current gear ratio is... are you going up or down?

The GV unit isn't a particularly steep overdrive.  Per their site, their overdrive and a 3.23 gives you a final drive of 2.52 in overdrive.  Definitely nice from an economy standpoint, but I agree that a 3.55, 3.73 or 3.91 would make for a more enjoyable car around town or when you're feeling silly.  Respective final drive ratios for those gears would be 2.77, 2.91, or 3.05.

The 8-3/4" should be more than up to the task for your setup.  Many cars have run quarters in the 9s with them.  Since you've got an overdrive and are looking at a fairly high (low numerical) gear, I'm assuming you're looking to increase your fuel efficiency somewhat.  If that's the case, it's a strike against the Dana, which adds considerable parasitic losses to your drivetrain.  Bigger internal parts take more power to turn, plus there's additional frictional losses from the larger surface area of gear engagement.  It also weighs a good bit more; unsprung inertia is not your friend.  Add in the additional expense and the Dana seems counterproductive to me.  On the upside, of course, it's nuclear-weapon proof and looks completely awesome under the car.