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1950 pontiac 239 engine swap to a pontiac v8

Discussion in 'The Hokey Ass Message Board' started by slimj714, Oct 9, 2012.

  1. slimj714
    Joined: Feb 17, 2009
    Posts: 32

    slimj714
    Member
    from Placentia

    Hey guys. I have a 1950 pontiac silver streak and i want to put a pontiac v8 to replace my 239. I want to keep my 3 on the tree tranny though. Is there a v8 that i can put straight in and will bolt up to my original tranny? Any help is appreciated. Thank you.
     
    blackjack likes this.
  2. flypa38
    Joined: May 3, 2005
    Posts: 530

    flypa38
    Member

    Might wanna ask on the pontiac 1950s yahoo group. Those guys will know.
     
  3. slimj714
    Joined: Feb 17, 2009
    Posts: 32

    slimj714
    Member
    from Placentia

    Thanks for the tip
     
  4. 55chieftain
    Joined: May 29, 2007
    Posts: 2,188

    55chieftain
    Member

    Your going to need an early engine 55-60 because the trans bolt pattern is specific to those years. Than a 55-57 bellhousing and clutch/flywheel set up . The trans itself was used from 37-55 , a light duty 5 bolt top cover. The stronger 6 bolt top cover 56-57 trans could be an option also but would require some work to fit. Finding a complete 55-57 engine/trans package would be your best bet. I don't think that trans is really going to like a bigger v-8 if your going to beat on it some.

    The rear end gears may not be to friendy to a v-8 either. 55-56 auto cars used a 3:08 rear gear and would bolt into the 50 housing. You would really need a 55 center section because of the pinion yoke differance between the 2 years to match what you have now.
     

  5. slimj714
    Joined: Feb 17, 2009
    Posts: 32

    slimj714
    Member
    from Placentia

    So any v8 55-60 will work. Im not looking to race just a cruiser and Im changing the rear end gears also. I just want w reliable car i can drive cross country. With good gears in the back my trans should be ok right? I want to keep a pontiac in my pontiac.
     
  6. The 55-57 bellhousing is the only Pontiac V/8 bellhousing that will work on your 55-60 engine and interface with your 50 transmission. If you find your rear axle gearing is a little too low geared you can use the 3rd member from any 37-56 Pontiac. I've always used a 55-56 3.23 gear. You can swap 3rd members in an afternoon. If you use a 56 third member, you'll have to swap the 55 and earlier flange on to the third member...another super simple job. Just remember to use lberal amounts of blue loctite on the threads...they love to loosen up while driving.
    My 41 had 3.90 gears and so did my 48...both got 3.23s and loved it.
    BTW, did you see where I said 55-60 engine? Any newer engine and bellhousing will not fit your transmission. A 59 or 60 engine is 389 cu.in and will pull even the fattest old pontiac around with ease.
     

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  7. do the pontiac rear end yokes your talking about have the same splines as a 9" ford rear?
     
  8. Lerenzo Rawson
    Joined: Jul 9, 2019
    Posts: 128

    Lerenzo Rawson
    Member

    Hey guys, iI just registered so this is my first post. Thanks for any answers i can get! So i know this is an old thread, but i'm also in the process of purchasing a 50 silver streak coupe with a cracked flatfead. It runs, but i want to do a full system pontiac swap. So my question is, does the year of the donor matter if i swap all 3 at once?
     
  9. Depends if you want to weld in side motor mount brackets for a 61 and later engine/transmission. The 55-60 bell housing MIGHT bolt up to your old straight 6/8 rear motor mounts....they look similar but I've never tried it. The old straight 6/8 engines used a front motor mount similar to the 55-57 V/8 front mount...again, I don't know if they're a bolt-in swap but they look the same.
    The 61 and later Pontiac V/8s used side mounts from the sides of the block to the frame brackets and a rear trans mount bolted to a crossmember under the transmission. Completely different than the earlier mounts.
    As far as rear axles...........the '50 rear end is the same as the 55-56 rear end....the 3rd members swap all the way back to 1937 to give several gear ratios. Earlier cars had lower gears. 1957 began the 9&3/8ths rear axle all the way up to 1964 except tempest/GTOs. The 57 rear end is supposed to bolt in a 55-56 car for a much stronger rear axle but I've never broken the earlier [37-56] rear end...in fact the only one I broke was a 57 rear axle shaft with a 389/4 speed.
     
    Lerenzo Rawson likes this.
  10. pontiac eng 013.JPG pontiac eng 002.JPG I happen to have a 56 Pontiac 316 car bellhousing. I think thats what you would need to install a 55 thru 60 Pontiac V8. The Truck bellhousing has a different trans a Muncie 318 was used on trucks and 58 and newer cars.
     
  11. Lerenzo Rawson
    Joined: Jul 9, 2019
    Posts: 128

    Lerenzo Rawson
    Member

    Gotcha. Luckily, i'm waiting on a bonus from the green weenie so ive got some time to figure out what i really want in there. Hopefully not too much time though! Much appreciated Rocky.

    Sent from my LM-Q710(FGN) using The H.A.M.B. mobile app
     

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