Putting a '62 401 in my 55 Special

Hey guys, long time no see. I have an update. I bought a rebuilt 401 with a thumper cam for my 1955 Special. (It was a sweet deal that I could not pass up.) It came with the original transmission. Apparently they both came out of a 62 Electra originally. Anyway, I'm trying to research everything I will need to do to swap the old 264 block out and keep the torque tube drive shaft. I have a 56 dynaflow but I was wondering if the 62 transmission can even be used with my setup. I'm really early on in my research for this so any direction and forum links would be much appreciated. I'm trying to search it out on the forum but I'm not sure where to start. Any ideas?

 

I need to add that I also have the 55 dynaflow that came in my car. I'm planning to rebuild one of the transmissions just to freshen it up. I have a '56 322 that came with the car but obviously the 401 trumps that one. So I have three different transmissions, not sure what condition any of them are inside but it doesn't matter because I'm going to refresh them anyway. I rebuilt a 4T60E in automotive school so hopefully this one won't be as difficult. The whole reason for doing this project is to learn so I'm not scared of it. I just want to do the right thing. I have manuals for the 55, 56, and 62 Buicks so between all of them I should have specs covered. I want to keep the original driveline to the rear if possible. I like the uniqueness of my car and I'm excited to keep it a cruiser.

 

I also want to put sparkplugs in the tailpipes to have flamethrowers.

 

Hello Ray,
I don't have the answers for you. The guys that do will answer your questions before long. I'm interested in the answers, so I subscribed to this thread/

 

that'll be cool !

 

You probably already know this, but the '62 401 won't bolt to the '55 or the '56 tranny. The '62 is a Dynaflow engine, so your best bet is to use an earlier torque-tube Dynaflow. As I recall, the last torque-tube Dynaflow was 1960. Any '57 to '60 Nailhead Dynaflow should bolt to your engine. Perhaps someone a bit more familiar with this type of swap can help you with the later Dynaflow to earlier torque-tube hookup. I don't know about Transmission length, torque ball interchange and so on.

 

I was hoping to find an adapter setup to bolt it up. But I may have to go the route you're suggesting. I'll look into it. Thanks!

 

Also a correction on the original car. The original car the 401 came out of was a 62' LeSabre

 

Externally, all 401s are the same; the LeSabre engine normally has lower compression then the Invicta and Electra.

 

Ok so I've decided to attempt to design & build my own adapter plate for mating the 62 401 to the 56 Dynaflow. I'm pretty confident that I can create a 1/8 to 5/16 thick steel adapter to mate them but my main concern is if the 401 engine has any external balancing issues that could arise from doing this. My plan is to attempt to shim the flex plate on the crankshaft to make sure the torque converter sits where it is supposed to on the input shaft with the increased clearance created by the adapter. Does anyone know if there are things I should consider regarding driveline balance doing it this way? That way I can maintain the original driveline (at least until I decide to convert it later with a caprice or something.) Any thoughts? (I am finally getting back to my projects after about 2 years worth of surgeries on my neck and hands.)

 

You can swap the early for late bell housing on the Dynaflow and the 401 will bolt right up.

Cheryl

 

Won't that change the tailshaft/torque ball in relation to the drive shaft though? I already have the 55 and 56 dynaflows along with the auto trans that came with my 401. Due to my budget, I'm trying to stay within what I have on hand for now. I'm also trying to learn to fabricate some things. This whole project was so I can learn to make/modify stuff rather than buy stuff. I figured if I was going to change the driveline, I would do the whole thing with an open driveline at a later date. This stage of the prject is basically to just get it on the road and going. What do you think?

 

You would be exchanging the housing on the front of your early transmission (transmission that fits the torque ball and tail-shaft) for the one on your 62 (late) transmission. That would allow the 62 engine to bolt up the the earlier transmission (early and late bell housings have different circumferences). It will not change any relationship between the trans and rear because all of the changes are in the front, or in front of, the transmission. I think you have to swap converters as well, but check wit a trans guy that knows the Dynaflow.

You will also need a rear sump oil pan and corresponding rear sump oil pick-up tube. The 55 Nailheads had a rear sump pan and your 62 has a mid sump pan. The early and late Nailheads have different oil pans meaning your 55-56 pan will not fit the 62 (different size and bolt pattern). You will need a pan from a 57-61 Nailhead (all rear sump) or a 65-66 GS Skylark pan (rear sump).

The early and late Nailheads are all similar in size and mounting. You may have to change the frame pad locations for the motor mounts to make the engine fit correctly in the engine bay and to the transmission location.

 

Thanks so much! I appreciate the help. I didn't realize the bell housings were removable. I hadn't looked that close yet.

 

Install a mid 50's Oldsmobile leaf-spring rear end. Hook up whatever tranny fits the 62 401 and cut a driveshaft to fit.
Saw that Olds rear swap years ago. Olds 88 and Buick Special and Century had similar frame measurements.
Others can add more info here I'm sure.

 

As far as the pan goes, I currently have the pan on the 401 and 3 early nailhead pans. I have two 55s, (a 264 and a 322) and a 56 322. I'm thinking what I may do is cut the bottom of the pan off from the flange and weld it to the bottom/sump of one of the other pans in order to make it fit. I think as long as I check my measurements, I can make it work. Thanks for the advice. This is helping me develop a game plan.

 

If you are learning to fabricate, and accept the challenge, then switch to an open driveline (like the Olds). I have collected parts and will be starting this on my ‘60 LeSabre. The dynaflow is a turd and taking advantage of later transmission gearing will give you a car with greater drivability! Im just doing a switch pitch 400 but OD trannys can be done as well. Talk to Russ at Centerville Auto for options

 

Open driveline:
The old torque tube design had so many different u-joints, you would be lucky to find one to fit, especially a mixed year engine/transmission combination.
Even the standard vs automatic, and 40-60 series vs 50-70 series u-joints were different as well as 1955, 1956, 1957, etc. A nightmare to even get a part number; then FIND the part.
A 1954-1956 Olds "88" leaf spring rear end (very strong) would be a match for the Buick Special and Century frame, and wheel well width. Even the brake drum size and leaf spring support, would be sufficient for the Buick size and weight.
I'm sure other leaf spring rears would fit with some modifications.

 

Napa has many conversion U-joints that might fit the bill?

 

I've been saying it & I will mention it again, a Jag front & rear assemblies are very attractive & fairly easy to do with average welding skills & fabrications. Another option. Rack & pinion, modern suspension, disc brakes front & rear, the size of evrything matches our Buick's, etc. etc. etc.