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Thread: Changing '65 Borg-Warner to GM powerglide

  1. #1
    President Member
    Join Date
    Nov 2009
    Fort Atkinson, WI, USA.

    Changing '65 Borg-Warner to GM powerglide

    Anyone have any experiace in changing the Borg-Warner 2-speed in my '65 Daytona to a modern street / strip powerglide or other modern automatic? I want to boost the H.P. and improve reliability.


  2. #2
    President Member
    Join Date
    Mar 2005
    San Jose, California
    Actually there weren't any BW 2 speeds. Some of them were set-up to start in 2nd gear. It is possible to use a different valve body for a 1st gear start. Since you have a Chevy engine there are of course a number of GM transmissions that could be fitted.
    David L

  3. #3
    President Member
    Join Date
    Feb 2011
    Pasadena, Ca
    If I were going to use a different transmission, I would step up to a 200 4 R. Go for the lock up torque converter and you essentially have a 5 speed transmission. Don't bother with a Powerslide.

  4. #4
    President Member t walgamuth's Avatar
    Join Date
    Feb 2012
    lafayette in
    I'd agree on the powerglide. Its not a performance transmission. It works well enough if you are not in a hurry and has a reputation for being bulletproof.

    There are competition versions built for sprint cars and such but those would be cumberson on the street.
    Diesel loving, autocrossing, Coupe express loving, Grandpa Architect.

  5. #5
    Silver Hawk Member
    Join Date
    Dec 2004
    Trochu, Alberta , Canada.
    I did this once. It was a bad idea. The logical choice these days would be one of the GM overdrive automatics, either the 700R4 or the 2004R. Both get you a low-gear start, and an overdrive top gear that makes highway cruising more pleasant and economical.
    Gord Richmond, within Weasel range of the Alberta Badlands

  6. #6
    President Member
    Join Date
    Jul 2010
    Above the Equator
    My '64 Daytona is 350 SBC powered and I converted to a 700 R4. Here is a list of things to deal with:

    1. The bat wing crossmember needs to be significantly notched and strengthened.

    2. The transmission cross member needs to have the bolt holes slotted (I dimpled the "dip" too) and you need the correct of three trans mounts (older style).

    3. I had trouble finding a dipstick to follow the firewall contour and and used EMT conduit brazing the original ends off the factory tube.

    4. You will need to adapt the cooling lines. I used a combination of the original and 700R4 lines and rubber hose. I also added a trans cooler from a Ford F-150 truck.

    5. Depending on the year you source the the trans from you need to replace the speedometer drive as some are electric. I used a Dodge truck cable to match the fittings on the 700R4 and the Stude speedometer. And you likely will need to change the drive/driven gear(s) for correct speed readings. When you get to that point note there are two different drive housings depending on the number of teeth you need on the driven wheel.

    6. You will need a proper length driveshaft. My Daytona is a 4Dr. and I sourced a 78 Buick Skylark (also 4 Dr.) shaft that was a "bolt in." The yoke from the Buick 350 matched the 700R4. You will become familiar with the "Broke Back" driveshaft angles.

    7. You will need to configure the shifter. I opted to forgo the column shifter and have a 90's Camero floor shifter covered with a cut down Cadillac Seville console (looks kind of "period").

    8. The 700R4 (and 200R4) use a TV (throttle valve) Cable and getting the angles and motion properly aligned can be difficult. Edelbrock makes a rather expensive adapter. I fabricated my own, but it took some time and adaptation.

    9. The 700R4 requires that the convertor lock up in 4th gear otherwise there is not proper lubrication in the trans. Every few years or so they changed how this gets wired. But basically you use a relay in conjunction with the 4th gear pressure switch to make it happen.

    Side notes: You need 3.54 or numerically higher rear gears. The 700R4 has a very low 1st gear (3.06) but I have 3.07's and it is a bit much in the higher gears. My 350 has the torque, but for city driving I just leave it in 3rd. If it goes to 4th the convertor must lock up and the engine even at idle is about 40 MPH on level ground. You will save about 50 pound in weight.

    All my stuff was sourced from Pick A Part. I must have looked under HUNDREDS of cars before I found a trans that showed signs of recently being rebuilt (a 1992 version BTW). I did all my own labor and the whole cost was about $200 but realistically most buy a new trans, pay for labor and the conversion is in the $3,000-$5,000 range.

    So, yea, that is my experience in adapting a "modern"* transmission. * Not too sure how "modern" a 25 year old transmission is. But it does have overdrive and a lock up convertor. With the GM engine at least you don't need the adapter bellhousing! Because I did it so cheap and because I wanted the "challange" I can't say it wasn't worth it. But with the 3.07 rear gears, and 90% of the time city driving I'm in 3rd (1 to 1 ratio) and really don't get the benefit is the overdrive/lock up convertor much. The 3.06 1st gear is the greatest benefit over the original BW trans starting in 2nd gear (and its goofy selector pattern).
    Last edited by wittsend; 06-14-2018 at 02:28 PM.
    '64 Lark Type, powered by '85 Corvette L-98 (carburetor), 700R4, - CASO to the Max.

  7. #7
    Silver Hawk Member
    Join Date
    Jun 2006
    Spokane, WA, USA.
    Agree, a 4-speed-overdrive automatic transforms any Stude in which it's used.
    Actually, the Champion would be the one which would benefit most from the swap. I've always wanted to do one.

    I did all my own labor and the whole cost was about $200 but realistically most buy a new trans, pay for labor and the conversion is in the $3,000-$5,000 range.
    For true, a talented, experienced, patient, (I must have looked under HUNDREDS of cars before I found a trans that showed signs of recently being rebuilt.) owner can make it happen for cheap.

    For those who are none of the above, Bow Tie Overdrives has it covered, albiet not for CASOs.
    A Typical 700R4/2004R Installation Costs Between $1000 To $2500, Requires Many Hours Of Labor, Skinned Knuckles And No Small Amount Of Thought, Ingenuity And Fabrication Skills. We Find A Very Large Percentage Of People Who Have Installed These Overdrives Have No Idea How They Should Behave Or What They're Actually Capable Of Doing. Most Hot Rodders Have Read A Number Of Articles Emphasizing How "Critical" The Set Up Of The TV Cable System Is To These Nifty Overdrive Transmissions. The Same Articles Offer Little In The Way Of A Reasonable Solution Concerning How To Set Up The TV System Between A Performance Aftermarket Carburetor And The Transmission. These Articles Usually Offer Impossible To Understand Diagrams Of How The TV System Cable Needs To Be Pulled Or A Procedure To Try. However When They Try The Procedure The Transmission Doesn't Behave The Way They Know It Should. The Results Is Most Of These Folks Become So Intimidated By This "Mystery" System That They Readily Accept Terrible Transmission Behavior Because They Fear Ruining Their New Transmission By Not Getting It Right! We At Bow Tie Overdrives Have Always Felt These Wonderful Overdrive Automatic Transmissions Should Be The Very Centerpiece A High Performance Vehicle And Not Have Their Potential Performance Compromised In Any Way!

    This Whole Section Of Your Web Site Is Devoted To Helping Folks Get These Wonderful Transmissions Operating Properly So They Can Enjoy Their New Overdrive Transmission To Its Fullest! The Subsequent Sections Will Offer A Comprehensive Explanation Of This Complex System, Simple Tools And How To Use Them So You Can Maximize The Performance Of Your TH700R4 Or TH200-4R With Absolute Confidence You Will Not Do Something To Damage It In The Process.
    jack vines
    Last edited by PackardV8; 06-14-2018 at 02:06 PM.

  8. #8
    Speedster Member
    Join Date
    Aug 2008
    Devon, Alberta, Canada.
    Very easy conversion to a THM 350 or 400. A buddy did my '66 a number of years ago and it was only a few parts from the wrecking yard and a couple of days to change over. The replies above lay it out pretty good. The 700-R4 or 200-4R also work if you want OD. Base your choice on the upper limits of your budget. You may regret cheaping out...

  9. #9
    President Member
    Join Date
    Apr 2006
    Union Gap, Washington, USA.
    I would convert to a standard transmission. I have 394 hp at the rear wheels of Pinkie is that enough hp for you? Hanging pedals are easy to deal with and if you do not go overboard you could use a Firebird hydraulic clutch linkage and transmission. I went with a manual clutch linkage in Pinkie way back when and am using a toploader truck transmission. I used a 3;00 gear ratio nine inch Ford differential so I do not need overdrive and the compound low gives me plenty of gearing when I have to haul something heavy off asphault.
    If you car is ugly then it better be fast.....

    65 2dr sedan
    64 2dr sedan (Pinkie)
    61 V8 Tcab
    63 Tcab 20R powered
    55 Commander Wagon
    54 Champion Wagon
    46 Gibson Model A
    50 JD MC
    45 Agricat
    67 Triumph T100
    66 Bultaco Matadore

  10. #10
    President Member
    Join Date
    Apr 2016
    Westbrook, MN
    I have NEVER heard of anyone wanting to switch to a powerglide!

  11. #11
    President Member Jerry Forrester's Avatar
    Join Date
    Aug 2007
    Douglasville, Georgia, USA.
    Quote Originally Posted by Jeffry Cassel View Post
    I have NEVER heard of anyone wanting to switch to a powerglide!
    You don't hang around with any guys in the drag and roundy round racing business, do you.
    Jerry Forrester
    Forrester's Chrome
    Douglasville, Georgia

    See all of Buttercup's pictures at

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