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Username Post: Posi Question        (Topic#349433)
HotRodg57 
"11th Year" Silver Supporting Member
Posts: 956
HotRodg57
Loc: San Marcos CA USA
Reg: 06-04-01
01-31-18 12:17 PM - Post#2722877    

Hey guys, I'm looking for a Posi for the 57. I found a guy that's got a ford 9" Posi, he says was in a 55 Camio, originally from a country squire wagon. He says the demintions from outside edge of drum to outside other drum is 65" he says the gears are 3. 25 with 31 spline axles. my 57 rear is stock with 3. 36 gearing. He's asking 900. Bucks. Question. What if any figment issues might I have to deal with? And do you all think this is a good deal?
Opinions welcomed.
Thanks
Rodger

Check out my Car Pics


Edited by HotRodg57 on 01-31-18 03:46 PM. Reason for edit: No reason given.

 

YOUNG57 
Contributor
Posts: 995

Loc: Tennessee
Reg: 12-06-10
01-31-18 03:24 PM - Post#2722895    
    In response to HotRodg57

Here are the widths of common rear ends. But these numbers do not reflect the spring perch type or placements. Only the overall length for wheel mountings. Most spring perches will have to be moved or replaced.

Rear end widths in inches
(wheel mount surface to wheel mount surface)

57.75 1962-1967 Chevy II/Nova
58.00 1978-1988 Chevy Malibu, Monte Carlo
59.50 1968-1982 Corvette
60.00 1955-1964 Chevy Car
60.00 1967-1969 Camaro
60.25 1968-1979 Chevy II/Nova
60.50 1984-1995 Corvette
60.50 1964-1967 Chevelle
62.00 1955-1959 Chevy Pickup
62.50 1968-1972 Chevelle
62.50 1970-1981 Camaro/Firebird




 
HotRodg57 
"11th Year" Silver Supporting Member
Posts: 956
HotRodg57
Loc: San Marcos CA USA
Reg: 06-04-01
01-31-18 03:51 PM - Post#2722900    
    In response to YOUNG57

Thanks for the reply. I'm sure no matter what I get, it'll need some mods. What I'm unsure of is the width of my stock orig. rear end is. I have discs on my rear end now, that I would like to swap over.
Rodger

Check out my Car Pics


 
56sedandelivery 
Dedicated Enthusiast
Posts: 5271
56sedandelivery
Age: 66
Loc: Everett, Wa.
Reg: 02-26-08
01-31-18 07:49 PM - Post#2722931    
    In response to HotRodg57

You want something 60" wide with stock spring location. Same as stock width. I am Butch/56sedandelivery.




Edited by 56sedandelivery on 01-31-18 07:51 PM. Reason for edit: No reason given.

 
raycow 
Honored Member
Posts: 27179
raycow
Loc: San Francisco, CA
Reg: 11-26-02
02-01-18 12:50 AM - Post#2722947    
    In response to HotRodg57

That Ford rear is 5" wider than the stock rear for your car. This is in addition to any spring pad spacing issues it might have. Are you asking about a 9" rear because you want to run wide tires? If yes, that one would require you to cut out the wheel openings or else jack up the rear of the car for tire clearance.

IMO, for $900 you should be able to find a used posi rear the correct width to fit inside your fenders, although you still might need to re-locate (or add) the spring pads.

Lastly, could you ask your seller what kind of vehicle a "55 Camio" is supposed to be? There was no El Camino in 1955, but there was a Cameo, which was a 1/2 ton stepside truck with fiberglass panels to make it look like a fleetside. According to YOUNG57's list, that would have had a stock 62" rear, so the Ford would have been 3" wider than that. What did the seller do for tire clearance on that one?

Ray

Those who choose an automatic transmission want transportation. Those who choose a manual transmission want to drive.


 
Bad56Sedan 
"11th Year" Gold Supporting Member
Posts: 863
Bad56Sedan
Loc: Pasadena, Texas
Reg: 04-29-04
02-01-18 05:58 AM - Post#2722967    
    In response to HotRodg57

What if any figment issues might I have to deal with?
65" is too wide, not enough drum outboard room
inner fender lip on 5-6-7 cars is aprox. 70½"

And do you all think this is a good deal?

unfortunately no because it doesn't fit

I would look around some more, but you know someone that wants $900 might take $700/500?
If so it still going to take another $1500 to narrow, axles and spring pads to make it fit.



VC56S 2 door Sedan, 38 Years

[image]http://chevytalk.org/sm/3564.jpg[/image]


 
models916 
Valued Contributor
Posts: 4740

Age: 66
Loc: Addison, IL
Reg: 05-28-10
02-01-18 06:38 AM - Post#2722970    
    In response to Bad56Sedan

If you are keeping everything else…..

https://www.ebay.com/itm/GM-8-2-55-64-Chev y-Posi-5...




 
HotRodg57 
"11th Year" Silver Supporting Member
Posts: 956
HotRodg57
Loc: San Marcos CA USA
Reg: 06-04-01
02-01-18 09:12 AM - Post#2722984    
    In response to models916

Thanks guys, those are all great points I had not considered.
The Posi in question was in a Cameo truck. I was hoping the mounting set up on truck was the same for the 57.
I do like that drop in unit, I will keep my eyes and my mind open.
Thanks
Rodger


Check out my Car Pics


 
Bluemeany 
Senior Member
Posts: 823
Bluemeany
Loc: Santa Clara, CA
Reg: 05-31-02
02-01-18 10:46 AM - Post#2722989    
    In response to HotRodg57

If your HP is less than 300, then you might consider finding a P-case hogs head that bolts right in without any mods or fabrication. Here's one: https://www.ebay.com/p/55-64-Chevy-Corvett e-55p-Re...

57 Hardtop 302 & 3 Speed stick w/OD;
93 Camaro Indy Pace Car


 
DZAUTO 
Senior Member
Posts: 8446

Loc: Mustang, OK, USA
Reg: 12-25-99
02-01-18 02:46 PM - Post#2723018    
    In response to Bluemeany

  • Bluemeany Said:
If your HP is less than 300, then you might consider finding a P-case hogs head that bolts right in without any mods or fabrication. Here's one: https://www.ebay.com/p/55-64-Chevy-Corvett e-55p-Re...




I never participate on the 55-57 sections any more because of the attitude as well as the very last time I was here I was cussed out, BUUUUUUUUUUUUT I feel compelled to reply to this so that one of the members is not misled.
THAT REAR ON EBAY IS NOT, REPEAT, NOT A POSI REAR!!!

Here is a side by side comparison of a 55-64 center section with 3.08 ratio, posi-left, non posi-right.



Attachment: 100_2114.jpg (62.06 KB) 3 View(s)




Attachment: 100_2115.jpg (77.36 KB) 4 View(s)






 
HotRodg57 
"11th Year" Silver Supporting Member
Posts: 956
HotRodg57
Loc: San Marcos CA USA
Reg: 06-04-01
02-01-18 05:45 PM - Post#2723029    
    In response to DZAUTO

Thanks DZ for your reply. I appreciate your opinion, I remember you from many years ago when this site was brand new! I am glad to know you are still around I am looking for the most "cost effective" way to put a posi under the 57. Suggestions??
Thanks
Rodger

Check out my Car Pics


 
DZAUTO 
Senior Member
Posts: 8446

Loc: Mustang, OK, USA
Reg: 12-25-99
02-01-18 06:26 PM - Post#2723034    
    In response to HotRodg57

PM sent.



 
Bluemeany 
Senior Member
Posts: 823
Bluemeany
Loc: Santa Clara, CA
Reg: 05-31-02
02-02-18 08:29 AM - Post#2723070    
    In response to HotRodg57

Ooops... Thanks DZAuoto for catching my error. I should have paid closer attention to the eBay listing. However, Finding a Posi section that bolts right in to the existing differential housing is not a bad way to go.


57 Hardtop 302 & 3 Speed stick w/OD;
93 Camaro Indy Pace Car


 
toro455 
"3rd Year" Silver Supporting Member
Posts: 399
toro455
Loc: Western NY
Reg: 06-15-02
02-03-18 01:09 PM - Post#2723206    
    In response to Bluemeany

I'm not a person who is very familiar with the '57 but the original car, I assume, has a functioning open differential now. Isn't there a posi carrier which would simply swap-out as opposed to trying to find a completely different rear end assembly from a different car? Is the issue the design for '57 wasn't that strong? I've swapped carriers in other vehicles and that seems like the best option in this case unless the '57 design too weak to handle the torque.

I can also say when you start to modify and rebuild anything the costs start to climb. I bought a 12 Bolt open and did all the work myself. To frame the job I changed gear ratios and I used new axles as well as of course the posi carrier.That was less expensive than buying a completely brand new rear end assemble from a place like Moser Engineering but not as much as some would think and my situation assumes zero labor cost. Moser btw does very nice work. I went that route on another vehicle.

Scott



 
55Wolfe 
Contributor
Posts: 135

Loc: Grandy, NC
Reg: 11-10-12
02-03-18 01:51 PM - Post#2723209    
    In response to Bluemeany

Doesn't the eaton posi unit bolt in without any mods to the stock case? Ithink it will unlike the chevy type posi. Also I think there was another case chevy made that was not the"p" case that would work. I'm old so I forget stuff so bare with me!
Dave {still drive a 55}
P.S. I think the left rear axle need 0.125 thousands removed also with the posi! I have a 57 case I put in my 55 that didn't need the rib in the case ground down for the posi unit to clear,It was a series 3 case but not a "p" case. I think it was an "N" case but not sure.



Edited by 55Wolfe on 02-04-18 08:37 AM. Reason for edit: No reason given.

 
DZAUTO 
Senior Member
Posts: 8446

Loc: Mustang, OK, USA
Reg: 12-25-99
02-05-18 08:31 AM - Post#2723408    
    In response to 55Wolfe

If anyone needs help or info on these early posi rears, I'll reply to any PM----------------------- -but I will not reply here (so far no one has provided any good factual information).



 
5Larry7 
"14th Year" Gold Supporting Member
Posts: 1921
5Larry7
Loc: Dallas, TX
Reg: 05-17-04
02-05-18 01:45 PM - Post#2723452    
    In response to HotRodg57

FWIW, I put a 8.5 ten bolt posi rear end in my 57. As the chart above indicates, it is 1.5 inches wider than stock per side. I got 8 inch wide wheels with 2 inch deeper off set and it all clears with 255/60X15 BF Goodrich tires. No rubbing even with spirited driving. The 8.5, while no 9 inch, is a pretty stout rear end.

'57 210, 327 cid, Holley MPFI, 700R4, A/C & more.
'51 Studebaker Starlite coupe, 350, TH400, GV OD.
'96 Replica of a 1950's Teardrop Trailer.


 
55Wolfe 
Contributor
Posts: 135

Loc: Grandy, NC
Reg: 11-10-12
02-07-18 01:53 PM - Post#2723667    
    In response to DZAUTO

You wont reply here, Oh no! Now I'm really sad.....



 
DZAUTO 
Senior Member
Posts: 8446

Loc: Mustang, OK, USA
Reg: 12-25-99
02-07-18 08:12 PM - Post#2723710    
    In response to 55Wolfe

PM sent.



 

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