Hey, So a customer of mine wants to put a 348 in his 50 Buick. The straight 8 blew up and he has a great running 348 sitting at home. He would like to keep the Buick 3 speed and torque tube. I've spent the last few hours searching but have not been to successful. Is there anyone who makes an adapter for this kind of swap? As far as I know the 348 and SBC use the same bolt pattern for the bellhousing, but I haven't found anything on adapting a 348 or a SBC to the stock Buick 3 speed.
Wouldn't say it can't be done......hell, almost anything can be done if you want to bad enough. But the primary issue is going to be the front of the Buick trans case. Pontiac, Olds and Buick manual trans of the late 30's thru the late '50s (and later in some instances) did not have a front bearing retainer and T/O bearing collar bolted onto the front of the trans like was common on Chevs and Ford/Mopar products. Those GM vehicles had a rather small bore thru the center of the bellhousing into which was inserted a flanged tube taht extended into the clutch area and on whick the T/O brg rode. The bellhousing further had a machined relief in the mating face that acted as the front bearing retainer when the trans bolted upto it. They also used a full gasket on the mating surfaces between the bell/trans and there was a small port to allow trans gear lube to drain back into the trans case that escaped the front bearing. Now, if this was the other way round, and you wanted to put a chev trans to Buick bell, you could just machine it 'open' to accept the chev collar, but that is not the case here. Aside from all that, there are two transmission sizes used in the GM cars in question, The so called "small" trans, also known as the "5 bolt top cover" model and the heavier duty, larger version with 6 bolt top cover. The latter is the only one worth considering as it is much stronger than the 5 bolt cover model. Also, in my experience, Buick rear ends are not all that great for durability. Bottom line, your customer, and you, would be far better off using a later GM trans compatiblewith the Chevy engine and converting the rear to an open drive differential. Using the Chev/GMC "truck arm" suspension arms is the easiest to adapt and will give very satisfactory result........done properly. That means the truck arms MUST be angled toward the center at their front, as close as possible to the driveshaft/u-joint with suitable mounting brackets. Ray
Sure glad someone else is thinking the Chevy truck 2 link trailing arm suspension for the Buicks too! Now if only ......
I think all of his stuff is to put later model transmissons behind early engines like the straight eight with late model Overdrive that the link goes to. The bigger problem here is a rather stout engine and rather weak transmisson and rear end comparatively speaking. A Chev Standard trans with a truck bar suspension and later rearend makes sense in this case.
Thanks for the response guys. The customer came by today (before I read everyone's responses) and we decided we were just going to make an adapter plate, use a chevy pressure plate with Buick clutch disc. However after reading the responses here and learning about the buick T/O bearing this may not work. I'm not very familiar with Buick stuff. The car is suppose to get towed over next week sometime. I like the idea of the chevy truck trailing arms. Once it gets here next week we'll figure out what to do. All I know is the owner wants a 348, and wants to drive this car this summer, so some how or another I'll make this work. And of course I'll keep you guys posted.
The trailing arms are somewhat long, so it might not be as easy as it seems. Interested in how the conversion goes. Keep us informed.
I have a set of new ones from Stock Car Products ready to go under my '40 Buick Super.......have taken the measurements, no problem with the length. Also measured my '41 Special......same thing, plenty of room. The "truck arms" really aren't all that long.......my SCP units are 56" overall and 6" of that goes under the axle housing, so they only need about 50" angling forward to a bracket or crossmember. So far as I know, the SCP units are dimensionally the same as OEM GM units. Ray
That's cool. That's the way to do an open driveline conversion in torque tube Buicks. Just need to fab the front crossmember.
I like it...W-motor in an 50s Pubic....those cars get pretty narrow toward the front of the engine compartment, but the 348 is so much shorter than that Eight...you'll probably need 4" bolt spacer for the fan off of the water pump. Let us follow your progress with pics. dj
Hey. So i said I would update with pictures, so here it goes. I'll start at the beginning. Step one, remove the old straight 8! The reason for the engine swap! And the 348. Its bored 60 over with forged pistons, 409 heads, 454 connecting rods, and a nice healthy cam. Were just running a 4bbl for now during engine break in. But once everything is working, we have a ready to run 6 carb set up for it! So to make this bolt up to the original buick transmission, was actually pretty simple. We got a chevy ****ersheild from a local speed shop and set it next to the buikc bellhousing. The two top bolts were the same, however the bottom ones were different, and the buick input shaft was 1 5/8" longer. There is also the small port the buick trans uses for lube, and the whole bearing retainer/ throw out collar ordeal. So what we did was maching up a chunk of 1 5/8" aluminum with both bolt patterns, and the buick bellhousing face machined in to it. Were using a Buick throw out bearing, and the rest of the clutch is chevy. It worked slick! So now with the chevy engine mated to the buick transmission, it's time to drop it back in. We just used a Hurst stye mount for the front As mentioned before, the 348 is a lot wider, and the firewall had to be removed for the valve covers and heads. It seemed like a shame to cut the firewall with so much room in front, but by using the stock trans and torque tube, this was pretty much the only choice. The customer was thrilled though, and loves how the engine sits so far back. He calls it his "mid engine buick" now haha. We did have to remove the shifter linkage from the column, and will be be changing over to a floor shift. This was there is still room to run the stock exhaust manifolds. Anyways thats where I'm at as of this morning. I'll keep updating as I go along.
Thanks for posting the updates. Nice work on maching that adapter for the trans, but I don't see the recess for the trans lube to drain back to the port in the face of the gearbox. Also, a gasket is required between the gearbox and your adapter. That is the lighter duty 5 bolt top cover trans......you, or your customer, will get some experience R & R that if he uses the available power. Best wishes on the project. Ray
The Buick 5-bolt top cover transmission is fairly weak and probably won't survive long behind a healthy V8. The gears are fragile. You might want to consider finding a 6-bolt top cover transmission or swaping to a modern 4 or 5-speed and converting to open drive.
The customer already picked up a 6 bolt, and will be doing a full rebuild on it before swapping it in. In the meantime he wanted to try the 5 bolt and see how long it lasts. You never know? Good eye on the recess. When I took the pictures it wasnt machined in yet, but don't worry, it's in there now The transmission won't even bolt up with out the recess as there is a little tab on the t/o collar that sits in the recess allowing the transmission face to sit flush.
I really appreciate the ingenuity to get these parts to fit together. I'm curious to see how the little trans will hold up. It has such a bad reputation, it just might last for years, lol.
Yea you never know, if you drive it with respect, it may last forever. My Dad built an O/T mustang that was originally a 4cly. He swapped in a 5.0L and a four speed but left the 4 clyinder rear end. Everyone told him it would blow apart. It lasted for years. He just recently changed to an 8.8 a couple weeks ago, not because the 7.5" blew up, but because it was a non posi and would not hook up at the race track.
Just posting a few updates. I'm hoping to have this done by the end of the week. The firewall is all finished up, and then engine / trans bolted in for good. Just hooking everything up now. Had to modify the bracket for the clutch pedal a little bit. The downside is you have to take out the two bolts to get the filter off. Its really easy to do though. The new shifter linkage. And I also found this for it!
Damn, you made it look easy. The 6-carb set up is a ballsy approach, so damn cool, but the four barrel would probably run better and perform right. Sweet looking Buick man, Best of luck with this cool swap. ~sololobo~
Thanks guys. Fabbed up an alternator bracket today and got all the pulleys lined up. I had to space all the pulleys out 1/4" so the belt would clear the hurst mount. I almost have the clutch linkage finished up. I'm using a Chevy truck clutch fork. Should have that finished tomorrow. After that, it's just wiring, radiator, exhaust, intake gaskets and break the cam in!
Sorry for the delayed update. I did get her running last week. Here it was just before I fired it up for the cam break in. Unfortunately however as we were trying to get it to fire, the HEI coil let the magic smoke out. I didn't really care for the HEI look anyways, so we replaced it with a MSD and it fired to life. Cam break in went fairly well with no major mishaps. It's still not 100% finished yet. Just minor stuff now. Should have the exhaust all done tomorrow. And I have to re-engineer the floor shifter. It worked great on the bench, put the ****** back in the car and now it's not working so good. Hopefully by the end of the week it will be all finished up though. The customer did take it for a trip around the parking lot this morning though
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