rob macwhirter Posted September 18, 2013 Share Posted September 18, 2013 Hi. Hope someone can help me out here ! I live in the Uk and have an original RHD 34 Buick series 90 trunk back sedan. I want to uprate the rear end ratio so she sits happy at 70-80 mph rather than 45-50 ! Whilst keeping the car as original as possible. Has anyone done this sucessfully ? Does anyone manufacture a differant ratio rearend that fits ? Any tips or leads greatly appreciated. Link to comment Share on other sites More sharing options...
Guest Goran Posted April 25, 2016 Share Posted April 25, 2016 Did you get an anser to this Rob i have the same problem pleas anser to goran@kynning.se Link to comment Share on other sites More sharing options...
Restorer32 Posted April 25, 2016 Share Posted April 25, 2016 You actually want to drive a '34 Buick at 80 mph? You're a better man than I Gunga Din. Link to comment Share on other sites More sharing options...
Matt Harwood Posted April 25, 2016 Share Posted April 25, 2016 51 minutes ago, Restorer32 said: You actually want to drive a '34 Buick at 80 mph? You're a better man than I Gunga Din. +1 I'd recommend an overdrive, but that asking for that much speed combined with ancient brakes and suspension? No thanks. With an overdrive you might be able to improve it to 60 MPH, maybe 65 MPH if you're really brave and don't care about the risks or tearing up the bearings, but too much speed in a car of that vintage is asking for trouble. Link to comment Share on other sites More sharing options...
Restorer32 Posted April 25, 2016 Share Posted April 25, 2016 One of the cars I really, really regret selling. An all original '34 90 Series Club Sedan. Even had unbroken exhaust manifolds. Would have made an excellent HPOF car. Still kicking myself for that bone head move. Sold it for $6k, triple what I paid. Thought I was rich. Link to comment Share on other sites More sharing options...
FLYER15015 Posted April 26, 2016 Share Posted April 26, 2016 Rob, I have heard of transplanting rear ends up to about 1953 cars under some 38-40 Buicks. My '40 is due for this operation soon. Check the H.A.M.B. web site or some of the links listed in the Buick forums. Mike in Colorado Link to comment Share on other sites More sharing options...
Owen_Dyneto Posted April 28, 2016 Share Posted April 28, 2016 What I would want to say to someone who wants to drive an 80+ year old car at 80 mph can't be printed here. Link to comment Share on other sites More sharing options...
Ben Bruce aka First Born Posted April 29, 2016 Share Posted April 29, 2016 On 4/26/2016 at 4:01 PM, FLYER15015 said: Rob, I have heard of transplanting rear ends up to about 1953 cars under some 38-40 Buicks. My '40 is due for this operation soon. Check the H.A.M.B. web site or some of the links listed in the Buick forums. Mike in Colorado Mike, the differential gear set will interchange from 1940 through 1955. I did a 1955 3.36/1 into my 1950. This dropped the RPMs about 650 to 700 RPM in top gear. Great for most driving. Second gear necessary more in slow speed [town] driving. Ben Link to comment Share on other sites More sharing options...
FLYER15015 Posted April 29, 2016 Share Posted April 29, 2016 Ben, Did you swap the whole rear end, torque tube, axles and brakes, or just the ring and pinion ? Keep in mind, mine is a 1940, series 90, with the longest available wheel base. If I could only do the gear set, it would make the conversion SO MUCH easier. Mike in snowy Colorado. 8" and still coming down. Link to comment Share on other sites More sharing options...
Matt Harwood Posted April 29, 2016 Share Posted April 29, 2016 3 minutes ago, FLYER15015 said: Ben, Did you swap the whole rear end, torque tube, axles and brakes, or just the ring and pinion ? Keep in mind, mine is a 1940, series 90, with the longest available wheel base. If I could only do the gear set, it would make the conversion SO MUCH easier. Mike in snowy Colorado. 8" and still coming down. The pumpkins on the smaller series cars are interchangeable as Ben describes, but the 90 Series cars have unique rear ends, so I don't know if a straight swap would be possible. I'm not sure about your 1940, but in '41, the Limiteds had a lot of unique parts, including the brakes, torque tube and rear end. I'm betting the usual pumpkin exchange wouldn't work on a big car, but would a complete smaller series rear end (like from a Century) fit under the car properly and would the Limited's torque tube bolt to it? The smaller brakes probably wouldn't matter and you might even be able to exchange backing plates and hardware, but are the rear ends the same width? Are the spring perches in the same place? I don't rightly know. Mike, how does your Limited cruise? My '41 Limited is pretty happy at 60 MPH with 4.20 gears and fairly tall 7.50-16 tires. If I go with radials, there are some that are about an inch taller, which should help a bit more. Is your 1940 significantly different? Link to comment Share on other sites More sharing options...
FLYER15015 Posted April 29, 2016 Share Posted April 29, 2016 Matt, I think you are right about the 90 series compared to the "smaller" models. It was only wishful thinking on my part. I think the '40 and '41 series 90 rear ends are the same, but I'm not sure. My only hope for an overdrive is cutting the drive tube and inserting an overdrive unit. I too run 7.50-16 bias ply tires (Martin B-16's) and she likes about 55-58 MPH. She does not like 65 MPH ! Mike in snowy Colorado. 8" now and still coming down. Link to comment Share on other sites More sharing options...
Guest wwayman Posted April 29, 2016 Share Posted April 29, 2016 I am restoring a 1935 F35 Olds and have the same problem. Nothing available for original rear end in terms of different ratios. I researched the possible "modern" axles and determined that 1960's Chevy Novas would be the correct width. I found one, Installed 3.55 gears (instead of 4.5something) and redrilled the axles for the wheel 5x5 pattern. Transferred the spring plates. I once asked a 35 Olds owner if he started in first or second when on the level. He said second, so I figure I am OK. I drive mostly on the level so starting in first gear should work. Car is still under restoration so I have yet to try it... Link to comment Share on other sites More sharing options...
Ben Bruce aka First Born Posted April 30, 2016 Share Posted April 30, 2016 (edited) On 4/26/2016 at 4:01 PM, FLYER15015 said: Rob, I have heard of transplanting rear ends up to about 1953 cars under some 38-40 Buicks. My '40 is due for this operation soon. Check the H.A.M.B. web site or some of the links listed in the Buick forums. Mike in Colorado Mike, the differential gear set will interchange from 1940 through 1955. I did a 1955 3.36/1 into my 1950. This dropped the RPMs about 650 to 700 RPM in top gear. Great for most driving. Second gear necessary more in slow speed [town] driving. Ben Mike, Matt may be correct. Someone else may be able to confirm. I just used the "punkin" from the '55. The procedure is pretty well documented in various forums. I even did a pictorial, I believe. Essentially , the entire rear end is pulled out from underneath the car. Pull the axles. Unbolt the torque tube from the rear end housing. Pull the torque tube after drilling or grinding the rivets holding the arms to it. Then the "punkin" will pull out the front of the housing, complete.The drive shaft is then removed from the pinion shaft. This was the most difficult. Willie [Old Tank] has a documentary on his web site. I would bet the internals are the same, all series. Mine came from a Century. That should be the same as a Roadmaster. The Limited of your era has the same engine as a Roadmaster. Therefore probably the same gears? Ben Whatever, if it can be done, you will LIKE it. I am able to cruse at 70 easily with mid 20s rpm. I have hit 92 and chickened out! Edited April 30, 2016 by First Born (see edit history) 1 Link to comment Share on other sites More sharing options...
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