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Technical Olds hydramatic - Is a stock 1949 hydramatic good for 300-400 HP on the street?

Discussion in 'Traditional Hot Rods' started by spacecowboy81, Dec 30, 2018.

  1. spacecowboy81
    Joined: Dec 9, 2012
    Posts: 66

    spacecowboy81
    Member

    I've dug through the Early Olds engine tech threads and also searched the forum for everything hydramatic and I see that the '54 - '56 dual range is the choice early Olds transmission. If someone has one to sell please PM me. My project is a '49 Olds that I'm now moving forward with after it sat idle for several years. I have a '57 371 Olds at the machine shop being rebuilt right now. One of the shop's questions is, what transmission am I going to use so he can balance it properly depending weather it has the factory flex plate or not. So I'm trying to come to make a decision on that and considering should I rebuild the factory '49 hydramatic?? This car is being built for the street and the engine will be mostly stock with the iron j2 manifold and 3-2 set up. I expect HP to be somewhere between 300 and 350.. Does anyone have input on how strong that transmission would be for occational street use behind the 371, I'm not looking to abuse it tooooo much : )
     
  2. dan griffin
    Joined: Dec 25, 2009
    Posts: 418

    dan griffin
    Member

    First off is the 371 a automatic or stick motor? If it is a auto trans you will need to put a pilot bearing in the crank. The flex plate has weights welded on the back save them. A 52-53 Olds hydro will bolt right in. Any 52-56 upright hydro off big motor like Cad,Hutson hairnet,Lincoln Will work with your bell housing. 54-6 Olds slant pan must use 54-6 bell housing and torus. Also get rear yoke for whatever trans you use.
     
  3. sunbeam
    Joined: Oct 22, 2010
    Posts: 4,044

    sunbeam
    Member

    There was a big change in 52 in reverse setup I don't know much about the earlier transes.
     
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  4. 48fordnut
    Joined: Nov 4, 2005
    Posts: 3,574

    48fordnut
    ALLIANCE MEMBER

    I ran a 371 with a 55 hydro yrs ago. Eng was balanced but I had a vibration about 1k rpm. Never fixed it. Car went 13.0s in 61.Awesome power.
     
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  5. Don't know much about those hydramatics, always used a stick tranny like the Lasalle or more recently the 37-38 Buick large case with the heavy duty Olds selector gears. Like rowing the gears I guess so I can't be much help here but I would ask Dan to put up a pic of that little known Hutson hairnet! Members here are curious I am certain:D:D
    Happy New Year Dan!
     
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  6. Sweet & Low
    Joined: Feb 13, 2014
    Posts: 248

    Sweet & Low
    Member

    You also might want consider a later model 700R trans with an overdrive. They make an adaptor to complete this conversion.
     
  7. spacecowboy81
    Joined: Dec 9, 2012
    Posts: 66

    spacecowboy81
    Member

    I don't know that the '57 371 engine I'm using has any variation from auto or stick as its missing the flexplate and belhousing, I received it as only a long block. Thanks for the info on bolt-ins.
     
  8. porknbeaner
    Joined: Sep 12, 2003
    Posts: 40,959

    porknbeaner
    Member

    In '57 the hydro didn't have a flex plate the part that bolted to the crank was part of the torus (a hydraulic link not a torque converter). It is actually a pretty heavy piece of steel.

    I have a slant pan hydro (dual range) in the garage that I may sell in the future. It is a B&M unit and I have not been in it so I can't say as to the condition of it but it will surely handle 400 ponies. The old dual range hydro was a heavy pig but it was as stout as the day is long.
     
    bobwop likes this.
  9. spacecowboy81
    Joined: Dec 9, 2012
    Posts: 66

    spacecowboy81
    Member

    Haha, even a guy under 40 like me knows he means a Hudson Hornet.:D I think I'd love a manual trans in this car, I'm just a bit overwhelmed while digging on the forum and seeing the parts collecting and fab involved to mate one up. Its not that I couldn't do it, I could.. but I'm trying to avoid obstacles that will keep this car off the road any longer. I think it would be super cool to have a vintage manual behind a 371 with 3 dueces! Can you give me some advice on the parts I'd have to find to put the 37/38 Buick manual behind my 371 and what would need to be fabbed? And then, how tricky is it installing a clutch pedal and what is the easiest option there for parts? Aftermarket? I understand from reading that the Lasalle manuals are rare to find so I've dismissed that in my mind.. I really like the idea of staying vintage speed on this.
     
  10. spacecowboy81
    Joined: Dec 9, 2012
    Posts: 66

    spacecowboy81
    Member

    Ah, of course, I was working with a '63 394 with a flexplate recently and that made me forget the '57 would have had a torus... not sure that I knew anyway.. that clears that up. Thanks. I think you should sell that B&M unit, after all... it would be happier rumbling down the road. :D Do you know if when you put the B&M hydro stick in the 4th gear position does it shift on its own like an automatic if you start from a stop? or does it stay only in the gear you put the selector in requiring you to shift through every gear? That's one thing I can't figure out so far from reading online.
     
  11. porknbeaner
    Joined: Sep 12, 2003
    Posts: 40,959

    porknbeaner
    Member

    They would auto shift, at least the ones that were not the blower specific unit would. Low is really low in them and one of the tricks that the led foot guys did was to leave with the selector in second and let it make the 1/2 shift on its own.

    The Hydromatic and the balls to the walls 394 that is on my engine stand will probably leave together. They are a nice pair, and I certainly could put the money to good use. :D
     
  12. GuyW
    Joined: Feb 23, 2007
    Posts: 496

    GuyW
    Member

    A hydro will take twice what you're talking about and come back for more. BTW I had a pickup with a 371, 2-4s, headers and a hydro and beat it pretty good. That tranny was used in US Army tanks, dump trucks, trash trucks etc.

    I think its fair to say that most of the blown Olds gassers back in the day ran their OEM hydros, hence, B&Ms business. I think some fuel dragsters ran hydros for a while. They were also popular for a while behind stout SBCs for drag racing, and were stock in some mid-50s GMC and Chevy 1/2T pickups.
     
    Last edited: Dec 31, 2018
  13. The 37-38 Buick large case tranny with the 6 bolt top cover is the unit used with the entire gear gut from a 51 -57 Olds selector tranny. There are threads on here regarding the work required to do the change over. First gear is non synchro and the tranny has a nice (imho) whine as you go thru the gears. Frank @F&J is running one now in his 32 behind his 371. You can search for posts from him for more info.
    Big issue is finding a 371 flywheel (Ross Racing may have new ones?), then there is the drilling of the rear crank for the pilot bearing and locating a clutch/brake pedal assembly. There out there and there is always a aftermarket unit that could be adapted. There is also an adapter to mate the Olds to a GM stick like a Muncie if you would prefer a tranny that is a bit newer. Lots to think about.
    Happy New Year!
     
  14. Todd553
    Joined: Feb 16, 2005
    Posts: 460

    Todd553
    Member

    My Pontiac made 557hp on the dyno. I'm running a B&M slant pan hydro. Not a lot of modifications on the B&M version. As GuyW said a stock hydro can easily handle 300-350. Might want to furnace braze the torus and modify a gear lockout to hold each gear. We made a shifter, but occasionally they show up for sale. A manual is avaiable called "Building a hydro for street or strip" it is an excellent reference.
    IMG_0517.jpg IMG_0553.jpg
     
  15. F&J
    Joined: Apr 5, 2007
    Posts: 13,173

    F&J
    ALLIANCE MEMBER

    Mine is a 324. But I should let you all know that just because it is a 57 371, it still may be drilled for a pilot bushing as they did have standard transmissions in 57 to 64 Rockets.

    Sorry to say that I just sold my last "complete set-up" 37 Buick trans with Olds gears, incl the bell housing, fork, flywheel etc this weekend!

    I also once had the correct standard trans pedals for the pre-54 Olds, but not anymore. :(

    I still have one "full race" 371 J2 engine w/stick flywheel...but shipping would be impossible for me. It's way too hot for a street engine anyways.

    By the way, 57-up Olds did not have the Hydra torus...they were Jetaway Transmissions.

    .
     
  16. Blues4U
    Joined: Oct 1, 2015
    Posts: 3,514

    Blues4U
    Member
    from So Cal

    Daaayyyuummm! :eek: :cool:
     
  17. bchctybob
    Joined: Sep 18, 2011
    Posts: 1,555

    bchctybob
    ALLIANCE MEMBER

    Todd553, every time you post pictures of that car my pulse quickens! Definitely among my top 5 favorite cars. Do you have more pics posted anywhere on here?
    As to the OP's questions, Don't bother rebuilding the old '49 trans, dig up a later version as stated and have it gone through but you'll probably be happier in the long run adapting a TH400 or other later trans.
    If you want a stick why not get adapters from one of the suppliers and use a Muncie or similar 4 or 5 spd. It seems sorta silly to go through all the trouble (and money) to end up with an antiquated non-synchro first 3 spd trans.
     
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  18. nochop
    Joined: Nov 13, 2005
    Posts: 843

    nochop
    Member
    from norcal

    I’m going with one of Ross’s 400 transmissions.
     
  19. paul55
    Joined: Dec 1, 2010
    Posts: 2,967

    paul55
    Member
    from michigan

    I have a complete '55 slant pan hydro. from a running/driving car. Complete with torus and flywheel.
     
  20. MANY years ago, I ran a '50 Olds Hydro behind a 394 in my '50 Ford panel. It held up well and I did not baby that thing. You'll have to have the back of the crank drilled to accept the Hydro pilot bushing and then have the whole mess balanced. Made for a good combination back in the day...
     
  21. hydroshawn
    Joined: May 27, 2006
    Posts: 335

    hydroshawn
    Member
    from Brenham,Tx

    The problem is to find someone that can build them the way B&M used to.
    I had one in my 55 Pontiac wagon with a 389 did 13s at Carlsbad all day!


    Sent from my iPhone using The H.A.M.B. mobile app
     
  22. GearheadsQCE
    Joined: Mar 23, 2011
    Posts: 2,083

    GearheadsQCE
    ALLIANCE MEMBER

    I have two Hydros that I would love to find a new home for. VERY REASONABLE, PM me for details.
     
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  23. Dwardo
    Joined: Aug 1, 2017
    Posts: 63

    Dwardo

    I also have a hydro that is probably just a core, as well as one I suspect is rebuilt. And maybe some other stuff like a welded torus. I, too would like to get rid of this stuff. They are very heavy so shipping would be a bear.
     
    F&J likes this.
  24. dan griffin
    Joined: Dec 25, 2009
    Posts: 418

    dan griffin
    Member

    I know the 57 is a fly wheel my point was the motor is external balance and the weights need to be removed and welded to the hydro flywheel.
     
    spacecowboy81 likes this.
  25. porknbeaner
    Joined: Sep 12, 2003
    Posts: 40,959

    porknbeaner
    Member

    Makes sense. You'll have to me sure that everything is clocked right I know you know that but someone else reading does not. Be pretty cool if you did a quick tech on that process when the time comes.
     

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