I've got a 1956 Buick Special that needs a motor. I bought the car knowing full well that it had no motor, so I knew I was in for a project. According to a guy I spoke with who is a fellow Buick lover, the 67-69 400 engine has the same number and positions of motor mounts as the 322, so it’s a straight drop in. Does anyone have experience with this to verify? He also explained that I’m gonna want to swap the transmission, as opposed to just the housing or using a conversion kit. The Dynaflow is still in the car, but it’s FUBAR, so I might as well get the ****** for the 400 instead of paying for a rebuild and a conversion kit. We discussed the need for a shorter driveshaft, as the later Buick ****** housings were longer than the Dynas, so I’m already expecting that. If this works, I’ll have to refind his contact info…
Unfortunately the information you have is incorrect. The 322 (and 264) mount near the front of the block while the 400 is more centered on the side. Bolt patterns of the brackets are different too. Bigger problem is you have a Torque Tube rear axle. The transmission bolts to a tube that bolts to the rear axle housing, the tube contains the drive shaft. The rear axle is pretty much held in place by the engine, the transmission, a lateral tie rod and the two rear coil springs. You will need to change the rear axle to either a 4 link or parallel leaf springs along with a different rear axle as it is designed for the torque tube. That unless someone has already changed the rear axle and suspension out. You might want to look under there before you start buying parts depending on your fabrication experience.
Ah, I forgot to mention that we're already planning to swap the rear. The original plan was to but the 400ci with a matching ******, the rear from the same donor car (my housemate is a fabricator, so making a mounting system will be manageable), and I might need a custom drive shaft due to difference in body length. This all hinged on the engine being a drop-in replacement. I could start messing with motor mounts, but at that point I have a Buick 350 4bbl and matching ******, which might make my life TONS easier. Are there any other GM engines (preferably Buick) that will bolt in with the given mounts?
I'm not sure on the later nailheads, but the later V6 and V8 Buicks all had side mounts. Better balancing and less stress on the aluminum bellhousings or transmission cases. Small block and big block Chevy engines have provisions for front mounts but again these are in a different position than the original nailhead mounts. Also, the correct usage for the Chevy engines with front mounts is bellhousing mounts,aka four point mounting. Using the front Chevy mounts along with the rear crossmember mount (three point) of a Powerglide/TH350/TH400 et al does put additional stresses on the transmission case. Some will argue that it does not matter and it may well not in 99 out of 100 instances. OK if you are 1-99 but ****s for number 100 with a cracked trans case. Fabbing side mounts is easy compared to building a whole new rear suspension system.
If youre changing the entire ***embly. This is no use to you. But, it may help somone else. The 264-322 belhousing will not any of the later engines.. It is larger than the other nailheads..
If your buddy is a fabricator and able to design a full rear suspension to replace the stock torque tube and rods he should be more than qualified to weld up a couple frame mounts for any engine you want to mount. And just for a reference for you , do a search for "truck arm suspension" to see a few buicks done up with easy to find junk yard parts and a simple mount. Posted using the Full Custom H.A.M.B. App!
Fabbing side mounts is easy compared to building a whole new rear suspension system. True. I was thinking to have just mounts for the rear suspension/axle fabricated, so perhaps I'll ue that spare Buick 350 which was supposed to go in my '72, and fab motor mounts as well. If youre changing the entire ***embly. This is no use to you. But, it may help somone else. The 264-322 belhousing will not any of the later engines.. It is larger than the other nailheads.. That actually does help a bit, as it narrows down options for an engine swap. Part of the issue is that I don't want to have someone rebuild a Dynaflow as I've heard they are finicky beasts and difficult to rebuild. Plus it leaves me stuck dealing with a torque tube. If your buddy is a fabricator and able to design a full rear suspension to replace the stock torque tube and rods he should be more than qualified to weld up a couple frame mounts for any engine you want to mount. And just for a reference for you , do a search for "truck arm suspension" to see a few buicks done up with easy to find junk yard parts and a simple mount. I think I mis-stated this, my apologies. I was going to have him fabricate mounting gear for the 67--69 rear which matches a 400ci engine. Keep the drivetrain as one matching piece (minus driveshaft) and just fit the mountings for the rear to the car by fabricating. If the 400ci won't drop in and match up, there's no point in requiring that engine. I can use any engine, though I will stick to Buick. I'll do that search and check out other folks ideas. Unless there's another, newer Buick engine with the same mounts, but at this point, that's seeming more and more trivial of a point.
Some interesting info. Next winter I'm going to be doing a swap from the transmission back. I can't wait to get rid of the dynaflow in my 55. I don't feel comfortable running at anything really over 55mph. It just revs the piss out of my nailhead... Going with a 700R4. It will so much nicer to cruise with and I might get better than about 5 mpg...
Thats why i just replaced my bad 322 and dynflow with good ones less headaches for the station wagon.Bruce.
Every auto transmission is a finicky beast if you don't know what your doing. I can't imagine they are so complicated compared to modern transmissions. I took my 56 caddy jetaway to a local shop for building and it works perfectly. They are also finicky beasts.
I still fail to understand why there'd be any consideration to finding a bolt-in motor if you're going to re-engineer the entire rear suspension on the car. Most motor mounts are a couple tabs with a hole or a tube for the bolt, some cars they sell you bolt-in kits to change the mounts over, that's how not complicated it is. You can put any damned engine you want in there, 350, 400, 455, Chrysler Hemi, SBC, whatever. It doesn't need to match the rearend, and a driveshaft is a driveshaft - a tube with a yoke at each end. Hell this month's Hot Rod a guy has a Studebaker with a Ford motor and a GM trans in it -
I still fail to understand why there'd be any consideration to finding a bolt-in motor if you're going to re-engineer the entire rear suspension on the car. For the exact reason I can't mount a Dynaflow for a 322 to my 70s 350; If the whole drive train fits together and the egnine just bolts up (as I was lead to believe), then it's less fabrication work and less trying to match things and search for what works. While I do enjoy that extra effort, I also enjoy just getting the whole thing together, swapping the parts out, and taking the car for a drive. It also means that I'm not doing as much structural work to the car.
Even another nailhead wont "just bolt up" as the mounts are different not to mention the bell housing size. I put a later 401 CID nailhead in my 1955 with a turbo 400 and changed the rear end to a 1962 Buick Electra unit which has the open drive shaft. Since you have a 1956 you can bolt in the center section for a 196?(1) to 196?(3) Buick with the open drive shaft and still keep the same axles so your bolt pattern matches front and rear. The 55 is different so I had to change the complete housing. We used an Art Morrison triangulated 4 link system and it improved the handling 300%. On the front you can use a kit from Scarebird that mounts 1976 Buick Riviera disc brakes and I also changed to a 605 power steering box. I have all this information on my yahoo flickr photo site and you are welcome to check it out and just ask me any questions you might have. https://www.flickr.com/photos/buickfan/sets/72157594218766363/
We are putting a 401/ 700r/ 8 inch, combo in a '55 Buick. It's not any more difficult than any other swap I have done. We are using a truck style rear set-up we got from "Hot Rods to Hell". You can make motor mounts to fit and the drive shaft is custom made.
On the rear suspension issue....just to be clear...The buick radius rods will not hold up with any axle to put under the car once the torque tube comes out. No mater what engine and trans you put in, the radius rods were not designed to support the axle alone and will bend and brake. The stock buick rear suspension can not be used in the way you are planning. Posted using the Full Custom H.A.M.B. App!
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