Transmission Interchange On Your Imperial

Imperial Home Page -> Repair -> Transmission -> Interchange

Question from Michael (Fluid Drive swap out):

I have a 1953 Chrysler with a fluid torque drive tranny.  I have purchased a 1953 Chrysler with a Powerflite tranny. Any problems I should look out for when I make the switch? 


From Phil:

Fluid drive engines had the bell housing cast integral with the block, while engines using the Powerflite automatic had a regular flange like most engines and the bell housing was attached to the transmission. You may want to look, but I don't think you can put the Powerflite or most late model automatics on a block that came originally equipped on a Fluid Drive car. There are some adapters for putting a manual transmission behind one of these, but I don't know the particulars about the conversion.

From Roger:

I believe that '53 has a one year only bell housing for the Powerflite that allows it to be mated to the same engine as the Fluid-Torque trans. '54 has the newer style bell housing that is PF only. I've driven '53s with both trans, and I think the Fluid-Torque is quicker than the Powerflite, even left in high range.

My '54 is slow off the line, but her rear end is a 2.93 instead of the original 3.54, so she's built for cruising, not street racing.

Follow-up from Arran:

It is my understanding that the extended bell housings were used from the 1951 model year until late in the1953 production year. It seems to me that this would correspond with the demise of the M6 semi-automatic and the introduction of the Powerflite transmissions. Every source that I have run across would indicate that this is the case.  It would seem to me that if it were otherwise then you would run across Powerflite without a bell housing. The M6 transmissions were also used on flathead six's which did not have that extension on the back of the block so obviously they were built with a bell housing as well as without, but I think that it was detachable. I do know that the late production 1953 Imperials did come with the Powerflite so a change in engine blocks would only make sense around the same time.  If I had a car with the Fluid Torque Drive or M6 transmission I would probably keep it. From what I understand from people that have owned them, they were a very reliable device. Another reason that I would keep one is that the M6 is fairly unique in that it is an automatic with a clutch pedal and, as such, has many of the advantages of a standard as well.

Addition from Muir:

That's right, all those extended bell housings were used up to '53 until the advent of the Powerflite. Interestingly enough, they appear to correspond with the small valve 331's too. The early Chrysler Industrials (Yep they even had "INDUSTRIAL" on the tappet covers) had this extended bell housing as well - although they were hooked up to Skilifts and combine harvesters and suchlike Biggest let down with the old fluid drive is that they are very slow shifting - the engine revs have to die down to provide the synchro between gears and in a hemi with a heavy crank etc this can be annoyingly slow As far as I can make out the fluid drive for most of the flathead era had just a fluid coupling, whilst those for the hemis had an actual torque converter which should make quite a difference... As far as performance goes, I read something pretty cool, and that was a letter (In a '51 Car & Driver) to the editor by a guy who had a Jaguar XK120, and he was asking why his friend who had a '51 Saratoga with a 331" hemi thrashed him to 60 mph.

Correction from Bob:

A slight correction--"straight" fluid drives (which were used on older Dodges 1941-1948) did not have the semi-automatic function (M-6). Although Chrysler specifications indicated Fluid Drive was standard, I have never know of any after 1941 that did not have the semi-automatic function, either M-3 (vacuum) or M-5 (hydraulic w/o torque converter) or M-6 (with torque converter.)

From Kerry:

The only data I have is that the 54 shop manual refers to both the long and short bell housing motors being available in 54, all with Powerflite. This seems to imply that the Powerflite was somehow adapted to the long bell housing.

Both the cast iron Torqueflites AND the Powerflites have removable bell housings so perhaps they simply made an adapter. If you are lucky this is what they did.

For those who don't have an early car, the first Hemis (331ci until early 54) had the bell housing cast as part of the engine block. This made the engine about a foot longer and another 7 million pounds heavier. Sometime in 54, they moved to the more normal engine block.

From Rolland:

Another item you will want to check is the crankshaft flange. I doubt that the fluid coupling bolts to the crankshaft in the same manner as the converter. Chrysler was famous for changing the crankshaft flange even when nothing else changed.

From Leo:

Here's a link to Capanna, they make various adapters for early hemi's. Maybe they can help you.

Question from Rich (1960):

Will a '60 Imperial trans bolt easily to a '72 440?


From Kerry:

No. You will need an aluminum TF to bolt to a 440. I went throug this trying to get a trans for the '57 project (had a 440 with it and a late model transmission. I wanted push buttons and integrated emergency brake. Only one year fits. I think it's '62 if I remember correctly. Depending on what you want to do in terms of a parking gear and emergency brake, other years might work. Some of the differences are described at:

One more thing to consider are the trannys themselves. It costs about 200 bucks to rebuild an aluminum TF + another 100 for the torque converter. That's in my part of the world. Prices vary. However, a friend just had over 400 in parts in his cast iron TF plus 400 in labor. On a previous cast iron TF the price was 900 bucks IF you can find anyone who will work on them. (or perhaps anyone who has ever worked on one before) Last thing you want is some kid who's been rebuilding imports saying "Sheeeit, if its a transmission, I can build it..."

From Rick:

Take the crank out of the 413 and put it in the 440 and hen the cast transmission will bolt up. The balance will match up, both engines are balanced internally and not on the tourque converter. Or you could use a '64 transmission which has cable the shift, late style torque plate, and a separate park cable.

Question from Brian (1963):

Has anyone ever swapped an early trans for a 66 & later trans ? I was told you can do this and still retain the push button controls. I could use the weight savings and would like to add a gear vendors overdrive unit. I have a heavily built aluminum head 440 and 4.56 rear gears but would like to drive on the freeway again.


From Mark:

I thought all the Chryslers got the aluminum cas 727 for 1962...

From Paul:

I'm with Mark on this, but I guess that we would have to ask what the difference is that your are looking for that makes you need to change to a later transmission to make your add on over drive work.

The aluminum case came out in '62. They added a PARK lever in '63. The shift lever replaced the push buttons in '65, and in '66 they replaced the 413 with the 440. I don't know if a torque flite from a 440 will simply bolt up to a 413 (sounds like you have a 440 in your car anyway), but I thought that they were the same internally. I am aware that there are internal differences between the early aluminum case torque flites and later ones, but I believe that the internal changes took place with the '71 model.

When I had my '65 Crown transmission rebuilt many years ago, they told me that they upgraded the guts to a '71 and newer model so that in the future it would be easier to work on and get parts for. I don't know exactly what they did or for that matter if it was even a very good idea, but the transmission has worked perfectly since then and I have had no problems with it. They did tell me that I would have to notify future shops that work on it if it ever needed repair.

From Bill:

Imperial Services is developing a conversion cable that will allow the operation of a '66 or later trans in a '62-'64 pushbutton car. They say they already have one that will hook up the '65 lever to the later trans. The '62-'64 type is supposed to be available by the end of the year. I bought their conversion cable to use a '65 console (on our Barracuda, also works with B body '65 consoles) with a '66 or later trans, haven't made the conversion yet but its a nice looking piece and nice heavy adaptor parts.

You won't be able to directly use your cables with a '66 or later trans because the '66 or later doesn't have the opening for the shift cable and adjuster wheel, nor the subhousing on the tailshaft housing for your park cable, nor would your output shaft accept the parking pawl. You might be able to change the output shaft and the tailshaft housing itself to take care of the park feature, but still have no direct way to hook up the shifter cable. Installing an early valve body in the later trans won't help because you still don't have the mounting for the shifter cable into the transmission case. This could probably be adapted by making a custom bracket to accept the shifter cable housing, something to clamp onto the end of the cable itself and adapt that to the '66 shift lever, and probably an adaptor on the lever to fine tune the length of the lever for the correct ratio so the travel of the cable when a button is pushed matches up with the travel needed at the shifter shaft.

From Steve:

We (Imperial Services) build conversion transmission mounts and shift cables to allow installation of the later ('66-up) Torqueflites into '56-'61 and '64-'65 Console and Column shifted Chrysler Corp vehicles. You'll notice that the '62-'64 pushbutton cars are conspicuously missing...

The '62-'64 pushbutton cars had a separate lever that operated a separate cable to engage the parking pawl. While it was a nifty system, the downside was that there were many extra parts required to do the job. In '66, Chrysler made this function internal to the transmission, eliminating the extra cable and hardware.

The problem with converting these cars is that two motions need to be combined into one. We've built a number of different iterations of conversion mechanisms for this swap, but have not yet found one with operation that is transparent to the vehicle operator, while being as reliable and safe as the original. We currently have a design on the test stand that looks promising, but it will probably be at least two years before it is ready for sale, if it continues to perform well.

My suggestion would be to find a good transmission shop in your area and have them build your '63 unit. Stock TorqueFlites will take a BUNCH of abuse, and will withstand fairly high torque combinations with very few modifications. The transmission in your '63 now is essentially identical to those found in the '63 Max-Wedge Plymouths and Dodges, with the exception being that the Imperial had a more robust (read "like a truck") coupling at the rear of the transmission.

Have you approached Gear Vendors about doing a pushbutton unit? If all else fails, Hughes Racing Engines grinds camshafts that take advantage of the Chrysler engine's larger diameter lifters, and make unreal torque numbers with relatively mild combinations... maybe make some minor changes and go with a 3.55 or 3.91 gear?

Question from Ken (1964):

I was just wondering what trannys will swap into my '64 Crown and still retain the pushbutton. Maybe I should rephrase that, what years of 727's will swap into my '64 and still retain the pushbutton.


From John:

I believe that '63 would be the only other year that you could do a direct swap.

From Bob:

1964 was the last year for the push buttons. On Plymouths, 1965 was also a cable operated trans, but the u-joints were different. X-type versus Trunnion. I believe I would just rebuild the existing one.

Question from Jeff (1968):

I have a '68 Crown 4dr HT with 440 which has a transmission which does not go into drive. 1st, 2nd, and reverse all work fine. It sat for several years and I think the seals dried up. I have access to a 66 Imperial Tranny from a 440. My question is.... Can I swap a 66 Torqueflite with a 68 Torqueflite? Are they the same? Will the torque converters interchange? Flywheel? I do plan to get the 68's tranny rebuilt and back in but for a fast turn around now could I swap em? 

Reply from Dan:

Both are actuated by rod-linkage (as opposed to cable), and neither have part-throttle kickdown. You probably should use the kickdown linkage that is on the car at present, but if the the kickdown lever is positioned differently between the two years (which I doubt), you may need the one from the donor car instead.

As for the torque converter, the main differences would be balance (internal or external) and stall speed. I don't think that '66 and '68 lo-po 440's are balanced differently, and the stall speed should be pretty much the same too. Unless they look very different (i.e., different diameter or balancing weights), just pick the one that is in the best condition.

FWIW, I ran a '66 Torqueflite & torque converter behind a '71 383 for several years without any problems.

Follow-up from Jeff:

I have a problem. I decided to buy a rebuilt transmission from a '74 Newport with a 400 and I am wondering if they can be interchanged. Also should I use the 440's torque converter and which flywheel should I use?


From Dave:

The transmission will bolt up. Use the original flex plate (not flywheel) that came with the 440 and index it to the crank flange with chalk or nail polish or paint, so that it goes back on in the same position. (BTW do the same with your wheels, especially if they are dynamically balanced on the car).

The flex plates are factory balanced, but why take chances? Unless the ring gear is bad on your original flex plate, it is a good idea to keep as much original hardware as possible when swapping parts on machinery. 

From Ken:

I don't see any problem with a '74 tranny going into a '68.

In fact it's a perfect straight across swap. (and I WILL be corrected if wrong!)

You must use the 440 torque converter as the 400's has a counter-balance. (you'll see two little square weights welded on)

From Joe:

Regarding trans swap:...... BALANCE

The 68 440 engine is an INTERNAL balance engine..........................

The 74 400 engine is an EXTERNAL balance engine..........................

(1)....if the 74 trans is used you MUST be sure that the trans input shafts are identical (splines differ in some cases)

(2)....the 68 converter MUST remain with the engine (because of balance) OR.... the small weights on the 74 converter MUST be removed.

(3)....flex plates should be the same!!

(4)....trans cases differ!!! be certain that ALL (needed) features exist...

IN A NUT SHELL:.. this swap will work!! ====================================

Just remember... the 440 is INTERNAL balance and MUST use a ZERO balance harmonic balancer and a ZERO balance converter

also remember... the 400 is EXTERNAL balance and MUST use the (special WEIGHTED harmonic balancer and the special WEIGHTED converter)

Many times people mix these parts and INCORRECT balance occurs, vibration is therefore present, and MUST be eliminated...

Just recently I was involved with the local Chrysler dealer, concerning this 'balancing act' A customer swapped engines and some components did not match, the dealer replaced u-joints, drive lines, balanced wheels, did front end alignment and spent hundreds of dollars (all customer money of course)

After a lengthy battle, the Chrysler parts manager, and a local engine builder/balancer both called me, to ask what could be done to fix this BALANCE

....I say this as a WARNING to you....NOT EVERYONE UNDERSTANDS.....

Question from Joran (1972 -> 1978):

I wonder if a 1972 transmision (727), can be used with an 1978 Chrysler 400cid engine?


From Bill:

As long as it is a big block trans, you can.

From Dave:

All big block Chrysler's have the same bolt pattern. One thing that you will have to research is the T/C (Torque Converter) balance & spline size.

When the engine was built it was balanced with the T/C bolted on. This balanced all the rotating parts as a unit. The weight were spot welded on to outside O/D of the T/C. The weights may look like the same, but a new T/C on an engine will probably need rebalancing. I believe there was at least 2 different splines used, like I said you will have to find that out. There is another balancing method. That one has each part balanced & when the engine with a T/C or flywheel is put together it has a proper balance.

This page was last updated October 12, 2004. Send us your feedback, and come join the Imperial Mailing List - Online Car Club