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View Full Version : 66 GTO needs a new rear end.



FatfreeGTO
01-05-2012, 02:27 PM
The rear end in my 66 is making noise and I want to replace it. I only want to buy this thing once so I'm going to give lots of info and be open to suggestions.

My current rear is the original one stamped WF (3.23 open) and measures 55 1/2" backing plate to backing plate. This leads me to believe it is the later "wide" version.

Some other info that is important. I am running a 17 x 8" wheel with 4.5" backspace and a 255/50/17 tire. I have also done a rear disc conversion, the measurement from the face of the disc where the wheel mounts to the other side is 61.5" All of this has lead to some minor rubbing on the sidewall of the tire due to the wheel well lips. Someday I would like to run a wider rear tire 275/40/17 or 285/40/17 I would get wider rear wheels to do this and a proper backspace, and massage the wheel well if need be. I believe that part of my rubbing issue is the backspace of 4.5" that I currently have.

So about the car engine made 344hp and 363 tq through a 4l80e trans. Engine and trans are staying, might do some upgrades to the engine in the future to top out in the 425-450 hp range. Might go to the dragstrip once a year and stay on street tires, otherwise its all street driving. If I ever did an auto cross or something I would be surprised, but it could happen.

I'm looking at both moser and currie for 12 bolts, a 9" would be overkill for me I think. I want to run a 3.73 rear gear, and have posi, limited slip, etc whatever is the best for driveability.

If I'm going to have one built I can custom order any width so should I stay with the current 55 1/2" wide version or have them build me something smaller to cure tire rub issues now and allow the wider rear tire in the future?

So here are my ?'s

How wide should the rear end be?

What spline axles?

What brand of differential?

What type of differential?

Who should do it? Currie, moser, other??

I appreciate any help I can get with this. I have spent far to much time looking around to try and figure it out and I'm getting no where. I only want to spend this money once and get the best bang for my buck so to speak.

Thanks!