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12 bolt rear upgrade

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JIM

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1970 SS Chevelle. 454, LGT-700 5-speed, 4.10 rear. 11.30@121mph
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Discussion starter · #1 ·
Over the winter, I'd like to pull the rear and do some needed upgrades.
I currently have a 12 bolt eaton posi with 30 spline Moser C-clip axles. I'd like to...
Change out the axles to a non c-clip style and install Ford bearing style housing ends that retain the axles. I'd also like to go to possibly a 33 spline and 1/2" studs. Can anyone offer up a parts list to do this job so I know what I am looking at here? In addition, what needs to be done to my Eaton posi to fit it with 33 spline axles? Anything else I am overlooking ??

Thanks,
 
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Discussion starter · #3 ·
I found the Moser #7900 housing ends (small chevy car for Ford large bearing/non c-clip axle). I guess I just whack off my current housing end and have these welded on?
Then measure and order axles? I've never messed around with this stuff before.
If I stick with 30 spline, I can leave my Eaton alone. If I decide on 31 or 33 spline, do I need an entire new posi or is there a part of my existing posi unit I can change out to make it accept 31 or 33 spline axles?
 
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#4 ·
I'd also recommend installing a set of ARP studs to replace those bearing cap bolts.
And consider welding the tubes to the center section and using a girdle support cover.
All welding should be done in a jig to retain the housing/axle tube straightness.
 
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Discussion starter · #5 ·
My tubes are already welded. It came that way when I bought the car 22 years ago. I also run a support cover already.
 
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#6 ·
get parts direct from moser, appro 400 for 33 spline axles w/ bearings and retainers, axle ends are about 80 for pair, these need to be put on with a jig for proper allignment( i have this and can do for others). if you have the newer eaton, then you should be able to put in the 33 spline gears set from randies R&P, they are about 130ish. the 33 axles are noticibly bigger, that is the way to go. tom
 
#7 ·
You can get a new Eaton with 33 spline axle gears in it or install 33 spline axle gears in yours. If you install them in yours you will have to get the holes in the case bored out to accept the larger axles. You can just order stock length 33 spline axles. The Moser housing ends are 2 1/2 inches wide, so you will have to cut the housing 2 1/2 inches from the outside of the flange on the end of the housing. It must be welded with a housing fixture to get everything straight. I have done this many times and have pictures of the housing with the fixture installed.
 
Discussion starter · #8 ·
Thanks for the info guys.
 
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#9 ·
big gear head said:
You can get a new Eaton with 33 spline axle gears in it or install 33 spline axle gears in yours. If you install them in yours you will have to get the holes in the case bored out to accept the larger axles. You can just order stock length 33 spline axles. The Moser housing ends are 2 1/2 inches wide, so you will have to cut the housing 2 1/2 inches from the outside of the flange on the end of the housing. It must be welded with a housing fixture to get everything straight. I have done this many insttimes and have pictures of the housing with the fixture alled.
Click to expand...
BGH, would you mind posting the pictures with the housing and fixture or even emailing to me.
 
#11 ·
BB_Mike said:
Let us know how much you end up spending on the upgrade.
Click to expand...
Mike, this is what it has cost me so far

12 housing c/w open carrier and axles $150.00
Ford ends..................................$80.00
Used 33 spline eaton posi and axles..................$450.00
New 3.73 gears...........................$195.00
Install kit.......................................$100.00
I still have to have the ends welded on so not sure what that it will cost
 
Discussion starter · #13 ·
big gear head said:
Jerry, send me an email and I'll send you some pictures.
Click to expand...
Send em to me too if you don't mind......:)
jvr70@msn.com


Mike, I imagine it is going to cost me about $500-600.
$80 for the pair of ends
$300 or so for a pair of axles
$150 for the labor to cut/weld on the housing ends.
 
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