Rear End Upgrade?

[Z Ya Later]

So, I'm thinking about doing some work on the rear end on the Z. I know I know, the 12-bolt or Ford 9 is the best way to go, but I'm on a budget lol. I want to run Moser (mainly from what I've heard about quality and such) parts and am looking at using the C-clip eliminators along with some custom alloy axles, new ring & pinion and maybe a new carrier posi unit and a girdle to top it off. New axle shafts are $295 and the C-clip eliminator kit is $139.95. Would the Moser R&P thick gear set be a good choice for strength, or should I go with Motive or Richmond gears? Which would be better, the stock unit or an aftermarket? Which would be better, 28 or 31 spline shafts? What are the advantages/disadvantages? Are there any yoke upgrades worth looking at (or any at all)? Anything else I could do while I'm back there? Thanks for the help guys.

[Squat13]

So, I'm thinking about doing some work on the rear end on the Z. I know I know, the 12-bolt or Ford 9 is the best way to go, but I'm on a budget lol. I want to run Moser (mainly from what I've heard about quality and such) parts and am looking at using the C-clip eliminators along with some custom alloy axles, new ring & pinion and maybe a new carrier posi unit and a girdle to top it off. New axle shafts are $295 and the C-clip eliminator kit is $139.95. Would the Moser R&P thick gear set be a good choice for strength, or should I go with Motive or Richmond gears? Which would be better, the stock unit or an aftermarket? Which would be better, 28 or 31 spline shafts? What are the advantages/disadvantages? Are there any yoke upgrades worth looking at (or any at all)? Anything else I could do while I'm back there? Thanks for the help guys.

Well the 31 spline axles are stronger but still not slick worthy. And I dont think that any carriers made for the 10 bolt are slick worthy. Truthfully, the 10-bolt wasnt made for Drag use.... its to small, carriers is too weak, and there isnt much you can do about it but get a ford 9 or a 12 bolt

P.S. if you have a mig welder and a nice junkyard you may get crazy and try to fab your own 9" or 12-bolt out of a explore or old chevy...... don't do it.... you will save time and money to by a Pre-fab one.

[Z Ya Later]

The thing is, she'll never see slicks. I may think about DRs on the back, but that's not a strong possibility. I just want something stronger than stock and maybe an upgrade or two. Thanks for the info on the axle splines. Is there any gain or loss in speed, traction or power delivery by going to 31 spline axles?

*** EDIT ***

After doing some poking around on Moser's website, I guess 31-spline shafts are for a Ford rear end. From what I can tell, the stock 7.5" only takes 28-spline shafts. Oh well, I guess that's decided lol.

[Squat13]

Ok well if its never going on slicks then g for it...... but also remember to factor in the cost of labor.......I mean your not relly thinking about installing a carrier your self (it you are best of luck and you are god)

[N20LT4Bird]

P.S. if you have a mig welder and a nice junkyard you may get crazy and try to fab your own 9" or 12-bolt out of a explore or old chevy...... don't do it.... you will save time and money to by a Pre-fab one.

You will save time, but NOT MONEY. I built a 12 bolt out of an old chevy truck. It was one of the hardest fab jobs ive done, but it saved me about 700-800 bucks to make my own.

[Joe 1320]

Well the 31 spline axles are stronger but still not slick worthy. And I dont think that any carriers made for the 10 bolt are slick worthy. Truthfully, the 10-bolt wasnt made for Drag use.... its to small, carriers is too weak, and there isnt much you can do about it but get a ford 9 or a 12 bolt

P.S. if you have a mig welder and a nice junkyard you may get crazy and try to fab your own 9" or 12-bolt out of a explore or old chevy...... don't do it.... you will save time and money to by a Pre-fab one.

All 10 bolts are not the same. It has more to do with the ring and pinion size. GNs use an 8.5 inch vs the f-body 7.5.... I know of numerous GN in the 9s with stock 8.5 inchers. My old prostreet elcamino with nitrous used an eaton 8.5 inch ten bolt and took lots of abuse and didn't fail. I suppose if you want to try 5K lauches with a big block under nitrous an 8.5 incer will fail, but from the average weekend warrior it's just fine. The 7.5 incher in the f-body is actually from the S-10 and that is indeed a crappy 10 bolt. I also have the opinion that a 12 bolt requires less power to turn than a 9" so you should in theory go quicker.

[Squat13]

All 10 bolts are not the same. It has more to do with the ring and pinion size. GNs use an 8.5 inch vs the f-body 7.5.... I know of numerous GN in the 9s with stock 8.5 inchers. My old prostreet elcamino with nitrous used an eaton 8.5 inch ten bolt and took lots of abuse and didn't fail. I suppose if you want to try 5K lauches with a big block under nitrous an 8.5 incer will fail, but from the average weekend warrior it's just fine. The 7.5 incher in the f-body is actually from the S-10 and that is indeed a crappy 10 bolt. I also have the opinion that a 12 bolt requires less power to turn than a 9" so you should in theory go quicker.

I was primarly talking about the stock 7.5 inch chevy 10-bolt found under the rear of a 4th gen f-body....

Also about the 9" in 12-bolt comparision..... I think the ford 9" is wonderful because of the fact that if you ever needed to change the carrier and pinion, the entire "pumkin" can be removed and replaced as one..... I have a buddy with a 5.0 that swaps his pumkin out at the track. He drove the stang there with a extremly low gear there and upon arrival will actualy change the entire pumkin out for a 4.11 gear in less than an hour, then ran consistant mid 11's on slicks, change the pumkin and drive home. He only did it once (I think he hated the fact that he lost two hours of race time) and now has a trailer but I think that is a pretty impressive thing to do. Hey within a hour, you could run 180 MPH and run 11's in the same car

[fastTa]

The 12 bolt definitely takes less HP to turn. If you are experienced, doing a gear swap takes no more or less time to do with a 9" or 12 bolt. You still have to unbolt and slide the axles out to remove the centersection.

[Joe 1320]

Speaking of changing ratios, I always wanted a Halibrand quick change rear. Not only a slick way of changing ratios, but they look totally bad@zz.

[Z Ya Later]

Speaking of changing ratios, I always wanted a Halibrand quick change rear. Not only a slick way of changing ratios, but they look totally bad@zz.

My cousin put a Halibrand in the 32 Ford he built. Check it out here...

http://www.dominatorinc.com/roadster2.html

Would there be a way to swap in an 8.5" out of a regal and make it work on the Z for about the same amount that I'm looking at to do this upgrade? I've never had problems with the rear in the GN, and its takin' quite a flogging and kept asking for more over the years. Also, if I stick with the 7.5", what diff should I look at, Auburn or the SLP Zexel-Torsen? Thanks guys.

[Aaron4TAMU]

If you are getting in the rear, go ahead and put in a Ratech solid spacer, and get rid of that flimsy crush sleeve.

[Z Ya Later]

If you are getting in the rear, go ahead and put in a Ratech solid spacer, and get rid of that flimsy crush sleeve.

I'm assuming there's a durability benefit with that, but is there anything else that it helps with? Anything else I should know? Thanks for the info guys, keep it comin'.

[Aaron4TAMU]

I'm assuming there's a durability benefit with that, but is there anything else that it helps with? Anything else I should know? Thanks for the info guys, keep it comin'.

The sole purpose of the solid spacer is to insure that the gears don't get out of alignment.

[fastTa]

The solid pinion "spacer" can be a good thing when properly installed and a very bad thing when not properly installed. The pinion depth must be measured and installed to within no more than .002". That is a pretty tight tolerance. If you set the pinion depth to far you will get lots-o-noise and the footprint will be too much on the toe. Too far on the heel for too shallow of a pinion depth and still lots-o-noise. Pinion depth basically dictates backlash so it is crucial.

Just make sure to have someone expereinced in setting up a rear end does the work.

[Joe 1320]

My cousin put a Halibrand in the 32 Ford he built. Check it out here...

http://www.dominatorinc.com/roadster2.html

Would there be a way to swap in an 8.5" out of a regal and make it work on the Z for about the same amount that I'm looking at to do this upgrade? I've never had problems with the rear in the GN, and its takin' quite a flogging and kept asking for more over the years. Also, if I stick with the 7.5", what diff should I look at, Auburn or the SLP Zexel-Torsen? Thanks guys.

What you choose will depend alot on the intended usage. For dragstrip performance, go with an Eaton. It is very strong and rebuildable. (That's what is in the 8.5 inch 10 bolt ala GN). The clutch packs are biased toward keeping the rear wheels locked for ultimate straight line traction short of a spool. The Auburn is a cone type and is what I call a throw away. When it wears, you can't rebuild it so you throw it away. For cornering, a Torsen (get the HD from SLP) applies the power to the ground much better in and out of the corners. Instead of applying equal torque to both rear wheels like an Eaton or Auburn, it applies torque to the wheel with the most traction. This is especially helpful when powering out of corners. The torsen will apply more power to the outside wheel in a corner, keeping the inside wheel from spinning or worse... making the whole rear step out and causing massive oversteer.