Has anybody out there put a 3 speed manual with overdrive behind a Buick straight 8? I have read that GM put 3 speed overdrives into the early Biscaynes and was thinking this might be a nice way to keep my 3 on the tree, eliminate my closed drive train, and get me some top end. I have a 51' 263 and have a 3:6 rear end gear. Looking to keep things period correct. Would love to hear ideas from those with experience.
Chevy had the O.D. available in the '55 and up 150, 210, Biscayne, Bel Air and Impala models. I have an O.D. tranny from a 1959 Impala in my '51 235". You first concern would be in obtaining an adapter to bolt the Chevy O.D to the Buick bell, if that's even a possibility.
A couple of things you need to know here. Adapting any post-'55 Chevy manual trans to the stock Buick bellhousing is a non-starter.....even with modifications to the Buick bell. I have been down this road and I am not a 'newbie'. In addition, the BOP manual trans of the late '30's thru the late '50's and into early '60's have what are called 'selector type' transmission shifter arms. One main lever is used to shift into all 4 positions......but what determines which 'pair' i.e., 1st/rev or 2nd/3rd, are engaged is the position of another smaller lever.....the 'selector'. What this means is, you must change the steering column jacket that uses the more common shift linkage that use two levers, one for each pair of gears if using a newer manual trans. As for adapting an open drive line, you have a couple of choices. You could use a Pontiac or Olds transmission which were always open drive as they would be a 'bolt in' in place of the Buick trans and, as stated above, use the selector type shift linkage. But they were not available with O/D in that era. One other thing. Those trannies came in two versions, the lighter duty "5 bolt top cover" and the heavier duty "6 bolt top cover"......the latter used on the Buick 320 engine and V8 Olds and Pontiac. The 6 bolt versions is physically larger and has a broader spaced bellhousing bolt pattern than the 5 bolt model and they do not readily interchange. You 263 trans is a 5 bolt model. The other option is an adapter assembly from Bendtsens in Ham Lake, MN, www.transmissionadapters.com. They offer an assembly that converts the back of the Buick block and crankshaft to duplicate the Chevy V8 (and later 6's). To that you can attach any Chevy stick or automatic transmission of your choice. I have their adapter for this purpose and can tell you they are very well made and sturdy. Not inexpensive, but very good quality. Adding an open drive rear axle is doable with several choices of suitable control arms. Ray
I looked into this a couple of years ago and used a kit for a different combo. But, I always keep them in mind when I get an idea like yours. http://www.transmissionadapters.com/Buick_straight_eight_263_320.htm From their home page: Bonneville world record holder 1952 Buick ran a 147 best pass using a 320 straight 8 with our adapter kit & a 4 speed trans.
This is the stuff of gold. Thanks for the quick replies guys. I am aware of the Olds/Pontiac transmissions and have searched for them but it seems that they are far and few between. As far as the selector type I was not aware of the differences and the change to a different steering column seems as though it would be complex. You stated that the change to a newer style trans after 55 is a no start.....does the Bendentsens adapter accomodate this? Basically I am looking to get a bit of top end and really enjoy the nostalgia of the three on the tree. Would I be better off waiting to find (and pay) for an Olds/Pontiac 5 bolt selector style transmission and then pair it with a better rear end gear? My fear is losing take off power. Another thought was to go to a 4 speed on the floor with the Bendentsen adapter. If paired with my existing rear end would this not get me more top end? Or is my thought process incorrect? If I bail on the three on the tree and go to a floor shifter is the OD (3 0r 4 speed) a better idea in conjunction with the Bendentsen adapter and my existing rear end? What other modifications would this pose? Ray I am curious what you did with your entire driveline? From your avatar I am guessing that Bendentsen adapter sits in that beautiful red Buick. Tell me more about it please! I also read your profile and would love to pick your brain on some sheet metal work I am contemplating.
Strait8 (the license number on my '38 Buick), the non-starter comment in my post was strictly in reference to using the original Buick bell housing with the later Chevy style transmission. As for the steering column change, it is probably not as complicated as it may seem. The column tube you see (aka "mast jacket") is clamped on a short tubular extension of the steering box and extends up to the steering wheel where a small bearing supports the 'steering shaft' inside and to which the steering wheel attaches. For example, one removes the steering wheel, the floor plate around the steering column, loosens the clamp at the base of the column and pulls it upward and off the steering shaft. The replacment coumn, with the correct style shift arms, is installed in reverse order. some modifications are very likely necessary to make this happen, but nothing very complicated. The other alternative is a floor shift style transmission. I answered you original questions as posed, but I agree with BJR above, I'd recommend you consider a Borg Warner T5 or a Aisin (Toyota/Jeep/Dodge) AX-15 5 speed. As for your original rear end....fahghettaboutit.....it is a torque tube enclosed driveline that does not readily lend itself to open drive conversion, though it CAN be done. But once you take the torque tube away, you have the same issues controlling the stock rear end as you would with other, and better, choices. The simplest and least expensive route is to use a Pontiac/Olds transmission and install an open drive rear end. If you use a gear ratio in the range of 3.25 ish to 3.55 ish, you will have adequate power for initial acceleration and still not wind too tight at 60 to 65 mph on the highway. I have a '49 Pontiac 6 cyl stick with what I would estimate to be a 3.50 ish ratio and it is just fine. Even a 3.08 ish would work as the Buick straight 8 has good low end torque. These old cars were geared so low because of the roads of the days in which they were built. Buicks from the '30s through the late '40s had as low as 4.40-1 quite commonly. I know, I've had (and still have) them. You can take off in second gear with that rear axle ratio! Lastly, that beautiful red Buick convertible is not mine, sad to say! Though it coulda been, had I been able and willing to part with a lot of shekels to get it when it was for sale. I just admired it so much that I appropriated the photo for my avatar. Ray
Possibly the easiest and cheapest way to a less screamy top end would be to switch to the rear gears from an automatic car, they were usually higher (lower numerical). It should be no problem for your high torque straight eight as long as you don't do a lot of driving in hilly country.
^^^^^^Good idea.I got so caught up in the later model stick shift thing I forgot about that alternative. Buick center sections through 1955 models will fit your earlier axle housing. I believe there is a 3.36 gear set in some Buick V8/Dynaflow cars in the '53/'54/'55 era. I'll see if I can confirm that, and which models, a bit later this evening and edit this post with what, if anything, I find. Ray
I'm in this camp with a Mopar straight eight project. I wanted overdrive, but didn't want a modern transmission. I picked up this Clark 207VO 5 speed from a late 40's -early 50's GM truck. It is kind of hefty for a sedan, but since my project was a 3/4-ton truck chassis, I didn't mind. I went through all the effort of figuring out how to bolt a GM transmission to a Dodge flywheel housing, and then decided I didn't have time to finish it. So, if anybody is ambitious enough to adapt this or happens to want to go fast in a GM truck, it's available.
What is involved in changing the the gear? Is this just a ring and pinion swap using my old axle housing and axles? I was able to look for parts and found a pinion gear. What else would I need to m ake this modification? Also, going from a 3:6 to a 3:40 what kind of speed increase would I really be looking at gaining? I did not find anything lower than a 3:4 but would consider it if it exists. I could not locate any references that show that Buick produced a 3:2 for this year. 1318723 PINION GEAR; 3.40-1 RATIO
You might get a 5% increase in top speed at the same RPM with the 3.40 gear set. An overdrive is generally about a 25-30% gain. The adaptor and the T5 are certainly the best bang for your buck. There are many ratios available in the T5 family allowing you a better low gear for better acceleration and the O/D giving you good cruising at a tolerable RPM. Warren
If your car already has a 3.60 rear gear ratio, not much to be gained by going to the 3.36. I either missed that or assumed you had something closer to a 3.90. However, to answer your question, if you found a 3.36 rear axle assembly, the idea would be to swap the center section/torque tube assembly into your housing. It MAY be the case where the torque tube length would differ one to the other. In that case, the torque tube and driveshaft inside may have to be exchanged as well. Just swapping the internal gears to your gear carrier housing is not particularly advisable, as it is very difficult to set them up in another housing with the exact mesh they have worn into and noisy gears is a likely outcome. All that is the reason I recommend changing the entire rear end aseembly for an open drive unit and biting the bullet on adapting or fabricating a suitable control arm system. At the minimum, you could use a Pontiac/Olds trans as discussed in prior posts, or go further with a suitable adapter and use any one of several suitable transmissions. As much I love old Buicks, the torque tube driveline is a real PITA when it comes to driveline improvements for modern driving conditions. Ray
I know this is an old post but if any answers were found since I'd sure be curious to know....I have a 264 bellhousing I was hoping to modify to fit a chev 3 spd. what exactly makes it not possible to modify the buick housing? Strait8 i'm sure you've discovered this already but in order to convert these cars to open driveline you would have to install a 4 link the locate the rear axle
The 264 V8 models used the lighter duty manual transmission, typically referred to by the number of bolts attaching the tin top cover..."5 bolt cover", vs the heavier duty version "6 bolt top cover". While otherwise very similar in appearance, they differ in case size and bellhousing bolt pattern. The bellhousing for 5 bolt models does not have a deep enough area to accommodate the lower bolts of the Chevy/GM trans pattern, so one cannot just drill and tap the needed bolt holes. If some sort of adequate extension were welded to the bellhousing to solve that issue, you are still left with the center hole problem. The Buick transmission (and Pont/Olds) did not have a bolt on front bearing retainer like Chevys. The rear face of the bellhousing is machined in such a way that it serves as the front bearing retainer. A tubular shaped part inserts into the bellhousing to provide a support for the clutch throw out bearing. You can, and I did, have the bellhousing bored to accept the Chevy front bearing retainer/TO bearing support, but the aforementioned lack of surface for the lower bolts remains. In addition, the clutch throw out fork and bearing must be considered. It is not that these issues couldn't be solved, but at what cost and effort? In spite of the cost, I succumbed to the temptations of ease and benefits of the adapter offered by Bendtsen's /www.transmissionadapters.com. Ray
I was going to do this on my 48 Super, bought a fully intact rearend for a few hundred bucks. that was almost 10 years ago now so it might be more. There is no need to rip out parts of the original drive train to get more top end, even if its really low you can keep the torque tube setup.
Depends on what you want to use for a transmission. The stock 5 bolt top cover manual trans used in Special/Super models is a relatively weak transmission. The Dynaflow is not weak, but is low performance. There are no easy replacements for either. If a Buick owner has a good trans and the only issue is the final drive, then yes, there are a precious few retrofit differentials that can get one as low (numerically) as 3.36. The Senior models that use the 320 engine have the considerably stronger 6 bolt top cover manual box, but not the desire for a Dynaflow alternative. A number of Buick Straight Eight fans seek a better choice of transmissions and that essentially requires the use of a transmission adapter and elimination of the torque tube driveline. Ray
My name is lu and I bought a 53 buick f-263 Straight 8, engine only. I built a stand for it and spent some time cleaning, tunning it up, all new wiring and now it’s a running component in a 48 Chevy split window longbed. The 4 speed on the floor is a Muncie sm420. I have a few things to finish in order to take it on a cruise,besides in n out of the garage. Sent from my iPhone using The H.A.M.B. mobile app
Hey, that's great! Would love to know more about your installation of the Buick 263. How did you go about attaching the SM420 to the Buick? Ray
IIRC, the SM420 is a clunky-shifting big truck 4-speed with a direct top gear. FWIW, there were a few Buick V8s found in GM medium trucks and school buses in the mid-50s and those were equipped with the SM420. I saw one in a local wrecking yard recently. jack vines
Do you want one that is bullet proof and pricey or one that leaks oil and is a bit fragile. If you have around 3 grand to spare the Gear Venders torque tube OD is a great unit and everything stays the same except for a bump in the torque tube (actually a 2' section). For half that you could get a Lloyd Young unit that uses the old Borgwarner OD unit. Also mounts in torque tube with no other changes. Lloyd has passed but I've heard someone else is providing the adapter and machine work. On my 37 Special I have a factory looking column shift, 2004R automatic OD, open drive line, and a 1970 ElCamino 4.11 rear end. This gives a 2.88 final in OD. Kept the clutch pedal so interior looks stock. I too like to keep them looking close to original.
I need that bellhousing! I just don't have the kind money necessary for an aftermarket adaptor and my car isnt "nice" enough to merit it...but i still think it would be neat to throw it together if I could get my hands on that trans or bellhousing
Jack, My enthusiasm for more info on the SM420 to Buick Straight is not the transmission itself, but the method of adapting the two........and to see how the Buick fits in the Chev pickup engine compartment. Ray
Believe it or not, I made pamphlets tracing everything out on print paper, thin poster board and sheet metal. Matched everything all up and had the input shaft housing diameter machined in an exact spot on the bellhousing in order to marry the transmission to the engine. I had to drill and tap new mounting bolts(for the lower part of the transmission) Sweating my but off not to ruin anything in the process. The scary part is that it all fits in the 48 truck, of course no mechanical fan but at some point I had to give a little. Electric fan and radiator are working just fine. I converted to 12 volts, points are being used in the distributor. I would like to put the generator and voltage regulator back in play, unfortunately I had to go with the alternator. I am getting desperate to drive it. I need to sleep with a clear conscience. If you know what I mean. Sent from my iPhone using The H.A.M.B. mobile app
Got any photos of any part of the installation, especially underhood? Did you have to move the radiator and, if so, how much modification of core support was required? I have a first design ‘55 (same as ‘54 style) GMC project pickup that came without an engine. I was planning to install Buick V8 but have been rethinking an inline might be interesting. I have a couple of options there, including a spare Buick 263 Straight Eight. Ray
I have tons of pictures from when I started till now. Give me a few and I will post the best ones that have better lighting and can see everything. Sent from my iPhone using The H.A.M.B. mobile app
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