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Technical Early Olds/Pontiac 9" conversion

Discussion in 'The Hokey Ass Message Board' started by Hyper Henry, Sep 17, 2018.

  1. Hyper Henry
    Joined: Sep 25, 2008
    Posts: 52

    Hyper Henry
    Member

    Thought I remember reading somewhere that guys are converting their early Olds/Pontiac rear-ends over so they except 9" Ford third members. Anyone ever done this?? What's all involved?? Pics would be awesome!!
     
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  2. 1934coupe
    Joined: Feb 22, 2007
    Posts: 3,595

    1934coupe
    Member

    I know it's been done, Henry Wilko one of the Wilko Bros. (NETO racers) said he had so much work and money in his Olds/Pont. rear that he did some comparison and found that the Ford 9" does work in the housing. I have no photo's but try a gasket and then try the axle they are both 31 spline. Good luck.

    Pat
     
  3. jimmy six
    Joined: Mar 21, 2006
    Posts: 5,370

    jimmy six
    Member

    Who'd want to do that? Ring and pinion on a Pontiac/Olds has a better lineup to lower drag. The gaskets on a Pontiac are round. 9" are not. If you want a Ford just get a new housing.
     
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  4. What jimmy said.
     
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  5. Hnstray
    Joined: Aug 23, 2009
    Posts: 11,051

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    Years ago a friend of mine, who is an excellent builder/fabricator, swapped a suitable Chevy truck pumpkin into a Diamond T axle housing to get a more highway friendly gearing for the small block Chevy transplant. Also, big issue was to retain the original Diamond T cast wheel centers. IIRC, he made an intermediate plate, like and adapter, to accommodate the differences in bolt pattern of the third members. I either don’t know or cannot recall (which is more likely) other details of things like axle splines etc., but do know it worked with a relative minimum of ‘fancy work’.

    Ray
     
    Last edited: Sep 17, 2018
  6. ^^^^^ Watched a conversion something like that done once. Only 2 things needed. One is knowing axle centerline and two is graph the 9" housing flange onto Olds/Pont housing.
     
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  7. DDDenny
    Joined: Feb 6, 2015
    Posts: 13,078

    DDDenny
    Member
    from oregon

    I can only guess, but wondering if this request is an aesthetic/traditional thing as I've had a couple Olds/Pontiac rears so I know the large visual presence they possess.
    I also understand the pre-nine inch Ford era (popularity wise) where the rearend of choice in the drag racing world was the Olds/Pontiac rear, nothing stronger could be found until the nodular cases came out, even then the early housings just didn't have the heft of the O/P housings.
    I propose that if strength is required and a period look is to be achieved the rearend housing found in the 57 Ford pickup (half ton only) would be a good choice.
    This is the one in my roadster, yes maybe a little overkill but I like the visual appearance of it in addition to the strength. It will take any Ford nine inch center section, these housings are also the strongest due to having no weld on axle tubes and ends as well as having the thickest tubes.
    The only negative is they are damn hard to find.

    20170326_094304.jpg


     
    Last edited: Sep 17, 2018
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  8. 1934coupe
    Joined: Feb 22, 2007
    Posts: 3,595

    1934coupe
    Member

    This is the one in my 57 Chevy, I just couldn't bear to put a Ford in my Chevy. Plus I have about 5 of these center sections and a 57 Pont. leaf spring housing.

    Pat
     

    Attached Files:

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  9. Hyper Henry
    Joined: Sep 25, 2008
    Posts: 52

    Hyper Henry
    Member

    Keep the input and feedback coming guys.
    Reason I am thinking of it is early Olds/Pontiac stuff is getting hard to find and only a couple of suppliers still make parts for them so price is usually double if not more. Mine is a drag race application and I broke the gears recently and also did damage to the pot and trying to find replacement parts is difficult as I said. 9" Ford stuff is everywhere and when racing sometimes you don't have weeks to try and find parts.
     
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  10. With out having the two center sections and/or housings to compare, it seems to me that some type of opening modification and perhaps bolt locations would need to change. If that is the case, and you are racing, I would just mod a 9" housing to fit the car instead of the other way around. Just thinking out loud, if the center section of the housing is modified to accept the 9", what about the axle shafts? Will the Pontiac/Olds axle shafts fit the 9" center? Would the 9" axle shafts fit the Pontiac/Olds housing? Cutting up two housing to make one seems like as much trouble as modifying the Pontiac/Olds to accept the 9" center. I get that the parts are hard to find, but don't understand why you want to modify the Pontiac/Olds simply to have easy to find (9") parts.
     
  11. Hnstray
    Joined: Aug 23, 2009
    Posts: 11,051

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    ^^^^^^^^^because we like to do stuff ‘our’ way....if we didn’t, we wouldn’t be Hot Rodders!:D

    I like overcoming a challenge....even if it’s more work.....but I can be stoopid like that sometimes......(some might say more often than that....:()

    Ray
     
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  12. 1934coupe
    Joined: Feb 22, 2007
    Posts: 3,595

    1934coupe
    Member

    My Olds/Pont housing alone cost me over $1000 for all the work done to it, 3"DOM tubes, brackets, a brace,Wheelie bar mounts, fill plug in top and shortening plus bearing ends. When a person with this type of rear runs out of Olds/Pont parts. The Ford is a good match. I have seen it done and with good results. If you have a stock Olds/Pont housing and want to put a Ford in it you would be wasting your time.

    Pat
     
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  13. junkman8888
    Joined: Jan 28, 2009
    Posts: 426

    junkman8888
    Member

    I found the information you're looking for on a racer's website a few years back and of course now can't find it, the process involved adding half-moons of material to the housing (in other words, make the opening smaller), they also used 9" ends and axles to complete the swap. I know some people think this seems like a stupid thing to do but just like everything else what racers used "back in the day" is getting scarce and expensive, the change-over to 9" pumpkins, housing ends and axles reduces costs.
     
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  14. Until you posted this I had not thought about such an idea even though I seen an Olds/Pont center section graphed to an old flat bed truck rear so it could roll along the highway comfortably. I do have a complete 57 Olds/Pont but I don't like the gears in it and am unwilling to spend the money just to put around. But then again, I hate to destroy a 1 year only housing. But in your case, go for it.
     
  15. Post 13. Axles can be made so housing stays the same as for brakes. I say this because I doubt that OP is running stock axles or stock 29's or 31 splines on his set up.
     
  16. 1934coupe
    Joined: Feb 22, 2007
    Posts: 3,595

    1934coupe
    Member

    I remembered something else I believe that the Olds/Pont. bgr. 88128R is the bearing of choice also. It beats the 2 piece Ford brg. I know someone will say something different but they sell Olds/Pont. ends for a reason.

    Pat
     
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  17. Tough to read; but here is something I saved from a while back.
    scan0001%20%28Medium%29 olds 1.jpg scan0005%20%28Medium%29 olds 2.jpg
     
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  18. DDDenny
    Joined: Feb 6, 2015
    Posts: 13,078

    DDDenny
    Member
    from oregon

  19. thirtytwo
    Joined: Dec 19, 2003
    Posts: 2,605

    thirtytwo
    Member

    To sideline the discussion slightly ... what happened? , and when? As I am a younger guy I never saw it happen , but in my lifetime 9”ers have been in everything

    Seems like most gassers I have seen that are survivors had olds rears..

    Most open drive hotrod survivors I have seen have 55-57 Chevy rears

    It’s kinda odd to think that the 9” came out in 57 , the good olds rear came out in 57 and the Chevy rear 55 ...but the 9” was adopted really late by drag guys and rodders alike... anybody have reasoning for this?
     
  20. Hnstray
    Joined: Aug 23, 2009
    Posts: 11,051

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    Just some random thoughts on the reasons.......even before '57, Olds (in particular) and Pontiac were tough(er) rear ends for hot rods and drag cars, they just got better in '57. The 9" Ford and weaker Chevy were the new kids on the block and took a little while to be discovered and in adequate supply to be adopted........probably other considerations were a factor too.......
     
  21. I saw an article like the one posted above which showed how to convert a Land Rover diff to a Ford 9 inch.
    I destroyed two 57 Chevy posi rear ends, and went to Dana 60. Right now I am running a 12 bolt, but it is slightly wide for the tires I am running, so I have a 31 spline 9 inch that I am narrowing.
    Bob
     
  22. Hyper Henry
    Joined: Sep 25, 2008
    Posts: 52

    Hyper Henry
    Member

    Guys I am simply looking for a more cost effective/easier to get third member. I have all the good parts in my Olds rearend including Mark Williams spool, steel caps and yoke, Strange 35 spline axles and even have the axle housing braced. I run a 727 trans and when you break a rearend/gears you usually do damage to the tranny as well. My last break I took the teeth off the pinion gear which wiped out crown gear which destroyed some really good parts in the tranny and even damaged the Olds pot somewhat. The biggest problem is there are only a couple mfg's for the Olds gears so they are double the price of other gears and not to mention no one sells a race pro gear for them.
    I don't want to completely swap out the complete rear-end because got a lot of money and time into the housing plus all the brackets (ladder bars, coil overs, wheelie bars, wish-bone, anti-sway etc) that would need to redone. So that's why I was thinking about the 9" pot conversion. plus I could get that complete pot in aluminum.....:eek:)
     
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  23. saltflats
    Joined: Aug 14, 2007
    Posts: 9,792

    saltflats
    Member
    from Missouri

    The pinion will be lower, so what will this do to your drive line angle?
    They do make a 9 inch pumpkin that takes the 12 bolt chevy ring and pinion, so the pinion will be closer to the P/O .
     
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  24. FWIW Moser sells new round back 9" housings supposed to be stronger than an original so there's an option.
     
    Last edited: Sep 20, 2018
  25. If you are busting up Olds Pont rear parts , you must have crazy HP. Or something else is going on. Just saying .:eek::)
     
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