FOUND:9 3/8 posi-questions

Discussion in 'A boatload of fun' started by buick455V8, Oct 27, 2005.

  1. buick455V8

    buick455V8 Well-Known Member

    I just found a '68 Wildcat 2 door with 64,000 miles and it has a 9 3/8 posi
    (it's tagged).The car is a non-air.$250.00 gets it.I think I will pick it up.Anyone know what gears are availible in '68?And I assume it will bolt right up underneath my '70 Wildcat convertible.Any guesses as to what gear ratio?Any help appreciated-Todd
  2. flynbuick

    flynbuick Guest

    3.07 standard in which case it would be coded PV on the tube.
  3. Go Buick Go

    Go Buick Go Woot!

    What condition is the whole car in? :Brow:
  4. jamyers

    jamyers 2 gallons of fun

    Double-check the sticky at the top of this forum, I think there's a difference between '68 and '70 mountings. But I'm prolly wrong, my memory isn't what it used to be, whatever that was....
  5. Well-Known Member

    As Jim said, but other ratios were available-I have a 2.78 posi from a '68 cat...
  6. Electra GSX

    Electra GSX Member

    1968 Rear in a 1970 Chassis may not work.

    Wildcat, Lesabre, & Electra used a very similar chassis and followed the same major changes each year their basic core design was changed. If you accept this, read on.

    I race a few Electra 225s. A Blue '69 STAGE 1 coupe and a Brown 1969 convertible with a 430. The convert is stock except for a Torque Tech 2.5" exhaust and a carb I rebult 15 years ago. It was always tough to get her to hook with one wheel peel. When she did, I was getting mid 15s at 89mph. It always took a few passes each season to get back into the swing of applying just the right power and timing to "romance" the tree without going up in smoke!

    in 2000 I bought a '68 Electra sedan rust bucket with 75K original miles, all service records, and posi. We drove her home in a harrowing tale of unmatched automotive bravery, leaking gas, with chassis holes you could put your hand through, hub caps flying off, a cloud of rust behind us! But that is another story!

    To my surprise the rear did not fit in my 1969 Electra. It was off by about 1/4" which was frustrating, as I thought "there must be something else wrong!" We pushed and pushed and almost got it to fit. We took it out, @$%$##&, and measured the small variance!

    Also, I did notice that the chassis design changed quite a bit from '68 to '69. The rails were boxed in '68 and the drive shaft was two piece. '69 & '70 are lighter with more of a muscle car setup instead of a luxo-barge arrangement of previous Electras. '69 and '70 are virtually the same underneath, 50 - 75 lbs lighter, and can swap rears. (Just try to get headers on a '69 that will fit on a '70 and you'll findout even more little differences however!)

    I then had local racing legend and Motorsports Hall of Famer, Gary Shaw, of Shaw Racing, trade the guts of the '68 for the '69. Now she hooks like she's got carbide cletes!

    No posi additive to keep her hard lock, as Gary suggested, and away we go, 15.3s all day long!

    Good luck!

    Favorite Quote:"STAGE 1 + Electra = Chrome Plated Brass Knuckles!" :3gears:

  7. Go Buick Go

    Go Buick Go Woot!

    I remember before the board got hacked or whatnot, there was a post about what fits where. I believe it was a board member Russ, who said that the rear under a 70 LeSabre w/o a 455 is a 10 bolt, same as a Skylark. Whereas the rear under the LeSabre 455, Wildcat, and Electra were all the 9-3/8 rear.

    So having one of each, I checked, and it's true. Although I now have a 10 bolt under the 455 car cos the 9-3/8 had a 2.73 open rear and I had a 10 bolt with 2.93. Not much of a difference, but something.
  8. buick455V8

    buick455V8 Well-Known Member

    Quarters have rust at bottom behind rear tire but the rest of the body is decent,interior is gone except for the rear seat base and dash which are black and perfect.Bumpers are straight and all 4 T-3 headlamps are there too.Car is silver.How about if I pull the tag off the diff cover bolt,can I/we decode it?
  9. Electra GSX

    Electra GSX Member

    Big Buick Rear end Codes

    It is not necessary to remove the tag, rear end cover, and count teeth to get the job done right.

    On the driver's side brake drum, if it is original, there is a code in yellow paint on the face of the drum. This code will tell you what your ratio is. I'll check my book later to decode it for you.

    Did you know there is a special PX code 3.91 option for the Electra and Wildcat? It was super rare and I have seen one in my life and a buddy of mine had another which he sold for big bux, and it was broken! :Dou:

    Good luck

    Electra GSX
  10. Phil Racicot

    Phil Racicot Well-Known Member

    The 3.07 ratio was standard (and the most popular) but there were economy and performance axles too.
    My 68 Wildcat 4 door hardtop had the performance axle option (a 3.42 posi).
    The 1968 Buick Chassis service manual I have shows the 2.78, 3.07 and 3.91 ratios as the only ratios available with positive traction on Wildcats but this information is wrong...

    Attached Files:

  11. telriv

    telriv Founders Club Member

    What kind of shape are the chrome on the grills & the plastic pieces behind the grilles??? I would be interested in these depending on $$$$ & shipping costs.
  12. Electra GSX

    Electra GSX Member

    I have not discussed this topic since 2005 on this forum but it is ever present as I am building a 500hp 1969 Buick Electra 225 Custom Sport Convertible with a 9-3/8 rear. It was rebuilt by the late great racing 24 hr champion Gary Shaw, of “And they walked away” fame. He took my open 2.56 and installed the 1968 2.73 posi in the 1969 carrier. The mounting points on the two rears were slightly different by about.25” or so and could not be swapped without modifications.

    So, now you have the back story, my real concern is the survival of the rear under 500hp/535T loading. I have heard that the pinion shafts fail. Looking at a few of these old and dried things on my rack you can see some evidence of discoloration, as if it was taking a lot of heat. Perhaps not getting sufficient oiling? Any thoughts or fixes?

    Michael Joseph
    1969 Electra GSX 12.33@116.6
    1969 Electra 225 Custom Sport Convertible 15.35@89
    GSCA NE #33 1983

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