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CaptMoe
11-05-2008, 08:39 AM
I have a stock 568 in my IROC right now and need to decide between the following two replacement units:

1. Large spline 568, 3.85 ratio, 4 pinion diff

2. Large spline 568, 3.77 ratio, OBX diff

How much top end can I expect to lose with the 3.77 final drive as compared to the 3.85?

Is there a big difference between the 4 pinion and the OBX?

Thanks...
Turbo3Iroc
11-05-2008, 12:13 PM
Moe, I made the same swap in my car and it's not that much of a difference. Less than 150 rpm. If you're that concerned with keeping the gearing stock 3.85 was an option on 523's but pretty rare. You could also go one size down on the tire size to make it equal again.
Xtrempickup
11-05-2008, 12:42 PM
just bite the bullet and get the quaifee and put it in the 3.85, its a dropin but more money
CaptMoe
11-05-2008, 01:53 PM
just bite the bullet and get the quaifee and put it in the 3.85, its a dropin but more money

These are complete trannies. I'd consider that a drop in as well...:thumb:
CaptMoe
11-05-2008, 01:59 PM
Moe, I made the same swap in my car and it's not that much of a difference. Less than 150 rpm. If you're that concerned with keeping the gearing stock 3.85 was an option on 523's but pretty rare. You could also go one size down on the tire size to make it equal again.

Not too concerned with it especially if it's that small of a difference.

Did you have an LSD installed as well or just swapped the gearing?

Is there a big difference between the Quaife and the OBX besides price?
t3rse
11-05-2008, 03:39 PM
Quality of construction and components. The OBX comes with some really crappy spring washers and bolts and may need some minor "adjustments" to make it work. I haven't heard of anyone grenading an OBX yet though.
CaptMoe
11-05-2008, 05:28 PM
Quality of construction and components. The OBX comes with some really crappy spring washers and bolts and may need some minor "adjustments" to make it work. I haven't heard of anyone grenading an OBX yet though.

That seems to be the typical response of OBX owners...
Turbo3Iroc
11-06-2008, 01:36 AM
The OBX is a knock off Quaiffe. If I didn't get a vote of confidence from Cliff and others in the community I would have spent the money on a Quaiffe. If you have someone like him do the work all of the "questionable" parts are taken care of.
CaptMoe
11-06-2008, 09:23 AM
The OBX is a knock off Quaiffe. If I didn't get a vote of confidence from Cliff and others in the community I would have spent the money on a Quaiffe. If you have someone like him do the work all of the "questionable" parts are taken care of.

Cool. For the price of a Quaife I can get a rebuilt tranny with an OBX that's been "upgraded". Seems like a pretty good deal to me.

Thanks for the input guys...
turboshad
11-06-2008, 11:10 AM
I'm running an A568 w/ 3.77 and OBX. Once I re machined one of the worm gears and upgraded the standard parts I've had no complaints. If you are getting one that is already working then I wouldn't hesitate on it. The only thing I would make sure of is that both axles slide in and out without effort. If they do that you should be fine.
CaptMoe
11-06-2008, 03:04 PM
I'm running an A568 w/ 3.77 and OBX. Once I re machined one of the worm gears and upgraded the standard parts I've had no complaints. If you are getting one that is already working then I wouldn't hesitate on it. The only thing I would make sure of is that both axles slide in and out without effort. If they do that you should be fine.

Thanks for the tip...
CaptMoe
05-08-2009, 07:38 AM
Update:

My OBX is in transit from TU and I picked up a brand new A568 from Ed Yeznaian in NY. I figured for a couple of hundred bucks more than a rebuild I'd get a new tranny. I also have a brand new clutch kit I got from Tim Helma.

I picked up a 3.77 ring gear and main shaft from an A523 from Jackson. So now I'm just waiting for a few other parts to arrive before I load up the IROC and head to Brian to get everything installed.

Can't wait...:)
Turbo3Iroc
05-08-2009, 12:08 PM
That is a NOS trans? What's the date on the tag?
rx2mazda
05-08-2009, 12:34 PM
I'm lovin mine Moe. Brain went through my obx and everything looked gravy.
CaptMoe
05-08-2009, 03:11 PM
that is a nos trans? What's the date on the tag?

12/14/94


I'm lovin mine Moe. Brain went through my obx and everything looked gravy.

I bet you're enjoying it. He told me they seem to have improved their build quality lately...