New rearend... to shorten or not shorten? - Chevelle Tech
Transmission & Driveline Transmissions and Differentials

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post #1 of 40 (permalink) Old Jun 1st, 19, 6:31 PM Thread Starter
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Chris
 
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New rearend... to shorten or not shorten?

So since I grenaded my diff at the drags, I figure I should look at going forward with a new rearend that I always intended anyways. The plan:

Moser 12 bolt
33 spline axles
Tru-Trac LSD
3.90 gear (I want to have a micro polished gear installed)
1350 pinion yoke
Ford ends
Wilwood disc brakes
1/2"-20 x 3" screw in studs

I intend to eventually mini-tub the car. This will allow me to run a 13.2" wide tire on a 10 inch rim at the drag race and road race. Should I get a 1967 axle which is apparently 1" narrower, and then run 1/2" spacers until the mini tub happens?

A lot of people are super against spacers, yet I have never actually seen a spacer cause a problem.

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post #2 of 40 (permalink) Old Jun 1st, 19, 8:13 PM
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Gary
 
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Re: New rearend... to shorten or not shorten?

prob easier to wait and narrow the housing at the same time as the mini tub installation. you have to remove the housing again anyway and it only takes 30 min or so to remove the carrier and pinion
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post #3 of 40 (permalink) Old Jun 1st, 19, 8:26 PM
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Re: New rearend... to shorten or not shorten?

Quote:
Originally Posted by -SS454- View Post
A lot of people are super against spacers, yet I have never actually seen a spacer cause a problem.

I ran one on one side of a 55 gasser with approx engine torque of 450 - ford 9" posi and 10" slicks on slotted aluminum wheels. Spring perches were not installed symmetrical so one tire rubbed on the inner wheel well.



I noticed some loose wheel studs on the spacer wheel after about 60 runs at the track.



Conclusion - I don't recommend them.
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post #4 of 40 (permalink) Old Jun 1st, 19, 10:16 PM
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Re: New rearend... to shorten or not shorten?

Quote:
Originally Posted by gnicholson View Post
prob easier to wait and narrow the housing at the same time as the mini tub installation. you have to remove the housing again anyway and it only takes 30 min or so to remove the carrier and pinion
X2!. The correct way to do this is to do the mini-tubbing first and then determine if the housing has to be narrowed. not the other way around!

Claude.
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post #5 of 40 (permalink) Old Jun 1st, 19, 10:36 PM Thread Starter
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Chris
 
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Re: New rearend... to shorten or not shorten?

100% agree, and that was the plan. But unfortunately I don't really have that luxury now. It's going to cost about $6500 for a new rearend, so I don't want to do that twice.

To repair the diff it will cost around $1000 with the chance of the same thing happening.

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post #6 of 40 (permalink) Old Jun 1st, 19, 11:07 PM
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Steve
 
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Re: New rearend... to shorten or not shorten?

Middle ground - Get a 9" of proper width. Then when you tub it, if you need to shorten it, just get a new housing and axles, move the pumpkin and brakes over, and resell the old housing and axles.

Quote:
Originally Posted by -SS454- View Post
100% agree, and that was the plan. But unfortunately I don't really have that luxury now. It's going to cost about $6500 for a new rearend, so I don't want to do that twice.

To repair the diff it will cost around $1000 with the chance of the same thing happening.

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post #7 of 40 (permalink) Old Jun 1st, 19, 11:14 PM Thread Starter
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Chris
 
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Re: New rearend... to shorten or not shorten?

i'm pretty set on a 12 bolt as it's lighter and doesn't eat as much power. But that is a good alternative.

Another question, is it worth it to get the adjustable LCA mounts?

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post #8 of 40 (permalink) Old Jun 2nd, 19, 12:44 AM
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Re: New rearend... to shorten or not shorten?

Just say NO to wheel spacers. With what you put your car through, you would be better off getting the shortened rearend and a set of offset wheels to fit for now. Losing a wheel in the 1/4 of a Chevelle will really tear up your body.

https://youtu.be/mJIn6gMlo6A?t=83
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post #9 of 40 (permalink) Old Jun 2nd, 19, 12:57 PM Thread Starter
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Chris
 
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Re: New rearend... to shorten or not shorten?

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Originally Posted by DUTCH MAX HEADWORK View Post
Just say NO to wheel spacers. With what you put your car through, you would be better off getting the shortened rearend and a set of offset wheels to fit for now. Losing a wheel in the 1/4 of a Chevelle will really tear up your body.

https://youtu.be/mJIn6gMlo6A?t=83
Why would the wheel fall off by using this style of spacer?


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post #10 of 40 (permalink) Old Jun 2nd, 19, 7:20 PM
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Re: New rearend... to shorten or not shorten?

Quote:
Originally Posted by -SS454- View Post
Why would the wheel fall off by using this style of spacer?

these should be a solid piece between the wheel and the axle flange

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post #11 of 40 (permalink) Old Jun 2nd, 19, 7:31 PM Thread Starter
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Re: New rearend... to shorten or not shorten?

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Originally Posted by VinceS427bb View Post
these should be a solid piece between the wheel and the axle flange
I don't understand what you mean.

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post #12 of 40 (permalink) Old Jun 2nd, 19, 7:47 PM
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Re: New rearend... to shorten or not shorten?

Quote:
Originally Posted by -SS454- View Post
I don't understand what you mean.
these spacers should be similar to a disc brake hat over the axle flange in thickness;
the disc brake hats effectively space the wheel out from the axle flange the same way that these pictured spaces do...
i'm running some with draglite wheels to keep from rubbing on one side

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post #13 of 40 (permalink) Old Jun 2nd, 19, 8:11 PM Thread Starter
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Re: New rearend... to shorten or not shorten?

Quote:
Originally Posted by VinceS427bb View Post
these spacers should be similar to a disc brake hat over the axle flange in thickness;
the disc brake hats effectively space the wheel out from the axle flange the same way that these pictured spaces do...
i'm running some with draglite wheels to keep from rubbing on one side
That's my thought too. I run 1/4" ones on the front wheels and I road raced with those.

I have had some of my screw in studs back off, but I was just talking with a friend and his screw in studs backed off and he isn't running spacers. Since I've put some loctite on them, no issues.

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post #14 of 40 (permalink) Old Jun 2nd, 19, 8:28 PM
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Re: New rearend... to shorten or not shorten?

I don't see anything wrong with solid spacers but never more than half inch thick.

Anything thicker than 1/4 inch spacers should have 1/2"x20 studs.
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post #15 of 40 (permalink) Old Jun 3rd, 19, 9:41 AM
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Re: New rearend... to shorten or not shorten?

Quote:
Originally Posted by -SS454- View Post
Why would the wheel fall off by using this style of spacer?
Personally, I would choose a Hub Centric spacer over a lug centric one referenced in your post. Requires a bit more homework on your part but a better option IMO.
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