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Technical 50' chevy car rear end swap?

Discussion in 'The Hokey Ass Message Board' started by 49' bomb!, Dec 27, 2016.

  1. 49' bomb!
    Joined: Nov 21, 2016
    Posts: 143

    49' bomb!

  2. Devin
    Joined: Dec 28, 2004
    Posts: 2,351

    from Napa, CA

    There is tons of info on here on this subject. I know first hand that 55-57 Chevy rear ends are pretty much a bolt in and only require drilling a new hole on the spring perch to properly center the wheel in the wheel well. Very easy to do. Use the search function to find out more. Nice car.

    Sent from my iPhone using The H.A.M.B. mobile app
  3. If you are up to welding in spring pads, the rear from an 80's Monte Carlo SS is a great width for these and most have a 3:42 ration in them I believe. I have a rear from an 86 SS in my 51 but it has 3:73 in it. a 3:42 would be a little better on the highway with the TH350.
    Last edited: Dec 27, 2016
  4. Is the Chevy car 50 feet or the rearend?
    X38 likes this.

  5. Rusty O'Toole
    Joined: Sep 17, 2006
    Posts: 9,614

    Rusty O'Toole

    The usual swap is from a 51-54 Powerglide Chev. 3.55:1 gears and a bolt in swap. If you can't find a used one, new gears are available for $350.
    Johnny Gee likes this.
  6. 49' bomb!
    Joined: Nov 21, 2016
    Posts: 143

    49' bomb!

    thanks for a nice reply!!
  7. 6-bangertim
    Joined: Oct 3, 2011
    Posts: 404

    from California

    Chevy Blazer 4-WD is pretty common, correct width.
    lawman likes this.
  8. barryvanhook
    Joined: Jun 17, 2011
    Posts: 625

    from Mesa, AZ

    My 49 fleetline has a 69 Camaro with a 3.55 posi.
  9. gimpyshotrods
    Joined: May 20, 2009
    Posts: 20,279


    If it is a 50-foot Chevy, I am going to have to recommend a DRW Eaton.
  10. Any of these G-body cars are about the same width and use the 5 on 4.75 bolt pattern wheels. I used an '83 cutlass 10 bolt in mine and even with 285/70R-15s and a hotrod 406 smallblock and a 12 inch clutch with a 4 speed, I never blew it up. The next owner blew the 4 speed but never the little 7.5" 10 bolt. Now, if you use one of these G-body axles you'll find they're a little narrower than the original axle. This worked great for me because I wanted to use my 15X8.5" americans on the back. They had an 1.5" positive offset which worked with the narrow axle.
    The '50 chevy spring center bolts are 1.5" forward of center so you'll need to redrill your lowering blocks to center the wheel in the wheel well. I made my blocks from 3/16ths steel welded to the axle housing and drilled the hole offset to the front. Worked perfectly!
    BTW, you might think about buying Chassis Engineering's upper shock mount crossmember for your car. These chevys have the upper end of the rear shocks mounted to the car's floorpan. I used aggressively valved shocks and it didn't take long to break out the floor. I bought the kit and it worked out great.
    Nailhead Jason likes this.
  11. A '55 to '57 Chevy rear works well, if you are using an open drive line.
    Same width as your stock rear, almost exactly 60".
    All you need to do is redrill the spring perch for a new locator pin hole, on the '55 to '57 rear end.
    1 1/2" forward on the spring perch, then 1/2 " inward. That's it, no custom kits needed, no welding needed.
    If you want new springs, POSIES has same width springs as your stock springs have now, no need to drill out and replace spring mounts on the frame.
    POSIE can make the springs at stock height or lowered, your choice.
    Nice springs with little effort to install.
  12. 49' bomb!
    Joined: Nov 21, 2016
    Posts: 143

    49' bomb!

    thanks for all the answers!!!
  13. That's the same reason I used the G body rear, so I could fit my 8 1/2's on it. I put a 255 60 on mine, 285 would be killer on it!
  14. Hdonlybob
    Joined: Feb 1, 2005
    Posts: 4,024


    If you do swap to a '55 Chevy rear end and do it by parts, make sure you check axle lengths..
    I used a '55 rear end gear and axle set up and put them in my '63 housing, as I didn't want to go thru any adaptations with the '55 rear end...
    All worked fine until I put the rear wheels on...then noticed they were loose.
    The axles on '55 Chevy's (and maybe 56's) are a different length than the '57 newer ones...
    Good luck on your swap..
  15. 49' bomb!
    Joined: Nov 21, 2016
    Posts: 143

    49' bomb!

    49\'chevy 008.JPG
    thanks for all replies! i'am still trying to figure this out?
    all that stuff from the 50's gone, or too pricey! does
    anyone know if I could use a S-10 or blazer rear end
    that is long enough to fit? what years, I need about 3.42
  16. Nostrebor
    Joined: Jun 25, 2014
    Posts: 1,221


    S-10 4x4 (not ZR2) will work. They are a smidge narrower and need spring pads welded on. There are three different widths of S-10 rears, so measure to verify.
  17. Not a single responder has asked if you still are using the old torque tube rear end and you do not say either...Makes a difference ,you know
    belair likes this.
  18. HUSSEY
    Joined: Feb 16, 2010
    Posts: 628


    Any of the Chevy S10 / Blazer / Bravada 4x4 rear ends will work. They measure about 59.5 from flange to flange. As noted, you'll need to weld on new leaf spring perches. Also, the rear axle locating pin on your stock leaf springs are offset so you'll have to compensate for that by drill new holes in your leaf spring perches.

    I think the S10 route would be the most economical. You may also consider a rearend out of an Explorer, same width as the S10. The only item to consider is that the driveshaft yoke/flange is offset which could result in driveshaft tunnel interference if you car is sitting low.

    I saw the link to Chassis Engineering Inc. earlier, they have several solution for drop in axles from 1960's cars but those rear ends are getting expensive.
  19. engine138
    Joined: Oct 5, 2007
    Posts: 2,276

    from Commack NY

    Chevy S-10 4x4 49.5 3.42
  20. 49' bomb!
    Joined: Nov 21, 2016
    Posts: 143

    49' bomb!

    it looks as if there I am going to have to do way with the torque tube.and I'm also going to have to deal with the 3 speed. it's still a work in progress. I want to thank everyone for their replies.
  21. slowmotion
    Joined: Nov 21, 2011
    Posts: 3,310


    First gen S10 V6 2wd/auto-3.42 ratio
    Second gen S10 2wd 4cyl/auto-4.10 ratio
    Just throwin' it out there from my experience.
  22. OR you could take the advice of Rusty O'Toole above
  23. Rusty O'Toole
    Joined: Sep 17, 2006
    Posts: 9,614

    Rusty O'Toole

    3.55 gear Powerglide rear end (51 - 54) is a bolt in, and so are the gears. New gears are now $400 but would still be cheaper than swapping transmission, driveshaft and rear axle.
  24. Lone Star Mopar
    Joined: Nov 2, 2005
    Posts: 3,320

    Lone Star Mopar

    There is a tech thread showing how to swap the original gears out for power glide here on the hamb. Seems like the guy paid closer to 50-100$ for his gear set. Try looking it up, should have what you need to know.

    Sent from my SAMSUNG-SM-N900A using The H.A.M.B. mobile app
  25. StefanS
    Joined: Oct 7, 2013
    Posts: 1,257

    from Maryland

    Which u joint assembly do you use to do this swap, the 3 speed or the powerglide?

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