Thanks to the ever-growing popularity of restored and cloned Max Wedge and Race Hemi-powered '62-'65 Dodge and Plymouth Super Stockers, many builders are quickly learning that the early ('62-'65) cable-operated 727 TorqueFlite does not accept the same torque converter as the later ('67-and-up) lever-operated 727.
The hassle is the cable-operated 727 and the one-year-only '66 lever-operated 727 have a coarse 19-spline input shaft, while the lever-operated '67-and-up successor has a fine 24-spline input shaft. Back in the late '60s and '70s, it wasn't a big deal as most aftermarket torque converter manufacturers offered something for everyone with coarse- and fine-spline high-stall replacements. But its been over four decades since Chrysler made the switch from 19 to 24 splines, and since maybe only one in a thousand 727s in use today is the early style, today's volume-oriented converter manufacturers have pretty much turned their backs on the early design. It just isn't profitable to stock such a low-volume item.
If you see this on the driver...
If you see this on the driver side of your 727 TorqueFlite case, it's a '62-'65 cable-operated model ('60-'65 904 baby TorqueFlites look similar). The other end of the cable is connected to the push-button control module inside the car (or a shift lever on console-equipped cars). The push-button control module uses sliding arms with ramps and cams to convert fingertip button inputs into a push/pull force on the cable. The in-out stroke of the cable acts on the valvebody inside the transmission case to affect gear selection. It's a simple bulletproof design that's only compromised by a misadjusted or damaged cable. The circular dial plate is threaded around the shift cable and is used for cable adjustment. Auto industry standardization banned push-button transmission controls on new cars after 1964. In 1965, the cable-operated 727 remained in production for one final year, but it was controlled by a lever on the steering column or by a floor shift on the console. No more buttons.
So if you want a high-stall 19-spline converter for your cable-operated 727, you won't find it at the local speed shop or in most speed merchant catalogs. Instead, you'll be searching out vintage equipment or spending extra for a custom job based on your existing core.
None of this is a big deal if you're building your '62-'65 B-Body into a free style car-you know, a basic hot rod or bracket bomber. Just swap in a later '67-and-up 727, toss in an aftermarket floor-mounted ratchet-shifter, and you're good to go with access to literally hundreds of available off-the-shelf torque converters.
But if you're a purist and want to keep the super cool push-button transmission controls in your '62-'64 Super Stocker, the whole input-shaft-spline/torque-converter scarcity deal is a real bummer.
Or is it? We got turned onto a neat and simple trick recently by the guys at Bob Mosher's Max Wedge and Race Hemi clone factory. It seems that by swapping a few carefully chosen parts from a '67-and-up 727, owners of cable-operated 727s can keep their buttons and still enjoy the benefit of a readily available, off-the-shelf, high-stall torque converter.
We should let you know that because Mosher's is primarily a restoration shop with a two-year backlog of customer project cars, they're not set up to handle inquiries on the procedure or to accept your transmission for conversion work. Instead, they share this information as a sort of public service and say any competent transmission shop can duplicate the results for you if you're not ready to do it yourself.
Follow along as Mosher's Steve Benoit outlines the swap and gives some pointers on dialing in your cable-operated 727 TorqueFlite.
By contrast, the '66-and-up...
By contrast, the '66-and-up lever-operated TorqueFlite uses a lever to control the valvebody and all gear selection functions. The transmission shown has a modified full-manual valvebody. As such, the throttle pressure/kick down lever-ordinarily stacked atop the shift lever-is absent on this example.
Transmission swappers beware!...
Transmission swappers beware! The '62-'65 transmission mount bolt holes are 4-inches apart (right). The redesigned extension housing used on '66-and-up 727s (left) is drilled differently (213/16 inches) and requires an A-Body mount when swapped into a pre-'66 B-Body. Notice the integral cable-operated parking brake assembly and different speedometer cable position of the pre-'66 housing. In 1966, Chrysler redesigned the extension housing (and main case) to move the parking sprag assembly inside the main case. This eliminated the need for the separate and confusing in-car parking sprag control lever used in automatic-equipped Mopars since the '50s. The '66 redesign directed all transmission control functions to a single column or console-mounted lever for simplified operation. But we still dig those push-button controls!
The 727 TorqueFlite used in...
The 727 TorqueFlite used in '62-'64 model year passenger car applications has a unique circular output flange (upper parts) and uses a specific ball-and-trunion driveshaft with a matching circular companion flange. In 1965, Chrysler switched to a slip yoke (lower parts). If you have the early type, don't fret. Both designs are fully capable of handling well over 800 hp and were reliably used in everything from Race Hemi Super Stockers to blown fuel-altered wheelbase Funny Cars.
OK, enough of the history...
OK, enough of the history lesson. Here's the crux of the issue. The finger points to the coarse 19-spline input shaft used through the '66 model year. The fine 24-spline input shaft (on right) arrived in 1967. These shafts engage inside the torque converter and because the 19-spline input shaft has a smaller diameter than the 24-spline shaft, it is possible to accidentally install a '67-and-up torque converter in a '62-'66 727. If you do, the car won't move an inch. More than a few Mopar builders have been stymied by this detail. Conversely, the input shaft diameter difference prevents '62-'66 converters from accidentally being installed in '67-and-up 727 transmissions. Thankfully, they just won't go in all the way. The parts in the middle are reaction shaft supports. While they both share a common 27-spline configuration, they are machined for different input shaft support bushings and are not interchangeable between cable and lever-operated 727 transmissions.
The design of the front clutch...
The design of the front clutch retainer is critical, so study yours carefully to make sure its compatible with the new parts you're swapping in. The '62-'70 front clutch retainers have round oil feed holes (pen points) and use a narrow 9/16-inch-wide bushing. If you see these features on yours, you must use a '67-'70 style input-shaft/rear-clutch piston retainer assembly and reaction shaft support. Late-style '71-'78 front clutch retainers are quickly identified by machined oil feed slots (rather than holes) and are only compatible with '71-'78 input conversion parts.
Here are the components you...
Here are the components you need to change to upgrade a cable-operated transmission to accept a '67-and-up torque converter. You're looking at the input shaft/rear clutch piston retainer assembly and the reaction shaft support. These goodies are hidden behind the front pump cover in an assembled transmission, except for the two splined extensions, which are visible after you pull the torque converter. Beware, these parts come in two varieties: narrow bushing, used from 1967 to 1970, and wide bushing, used from 1971 through 1978. You cannot mix parts between the narrow and wide bushing versions. The component set must be from the same-vintage donor transmission. Your best bet is to scavenge them from an unmolested donor or source them from a competent transmission rebuild shop that's aware of such intricacies. Expect to pay around $100 for clean used parts.
Identifying the conversion...
Identifying the conversion parts for mutual compatibility with the front clutch retainer is a simple matter of taking careful measurements and observing details. On this reaction shaft support, the tape measure shows the 9/16-inch contact journal used on '62-'70 transmissions. If yours measures greater than 9/16-inch wide, it's for a '71-'78 wide bushing application and must be matched with a '71-'78-style front clutch retainer and input-shaft/rear-clutch piston retainer assembly.
A classic hassle with TorqueFlite...
A classic hassle with TorqueFlite of all types is limited access to the bolts attaching the flex plate to the torque converter drive lugs. An excellent remedy is to cut an access area in the bottom of the case using a hole saw and pneumatic cutoff wheel (or reciprocating saw). The opening eliminates wrench-to-case interference, which leads to rounded bolt heads, inaccurate tightening, busted knuckles, and wasted time. The gap has no impact on case strength as long as the cut line intersections are gently curved to prevent crack-inviting stress risers. While you probably wouldn't want to do this to the numbers-matching transmission case in your Hemi Super bird, it's super practical for the average street and strip stormer.
Identifying the input-shaft/rear-clutch...
Identifying the input-shaft/rear-clutch piston retainer assembly is a simple matter of counting the number of sealing rings present on the area indicated by the pen. If you see two (like the model shown here), it's a '67-'70 unit. If you see only one, it's a '71-'78 item. Naturally, you also must confirm that the splined end of the input shaft has the desired 24-spline count, thus opening the door to modern torque converter offerings. We won't bog you down with the installation process as it's no different from a typical 727 build . . . as long as you follow our tips and use the properly matched components we've outlined.
Mosher's Steve Benoit uses...
Mosher's Steve Benoit uses a punch to gently drive the stock race out of the empty transmission case. It's important to work in a gradual circular pattern to keep the race from getting wedged. Always be sure to remove the set screw located at the 6 o'clock position of the race prior to any removal effort.
While you're inside your TorqueFlite,...
While you're inside your TorqueFlite, take the opportunity to replace the stock-over running clutch assembly with a quality bolt-in replacement from A&A Transmission. The stock unit (left) is press-fit into the case and is prevented from rotating by a shallow serrated interface with the case and a small set screw. If the rollers and springs are upset from their proper positions in the outer race due to driveline breakage or improper burn out technique, the steel race can easily break loose and spin in the soft aluminum case, triggering catastrophic-and potentially deadly-transmission destruction. Bolt-in over running clutches, also known as sprag assemblies, eliminate the threat. We installed the standard A&A 12-roller bolt-in sprag (right). It's available as PN K22961E for about $110. Even greater insurance is provided by A&A's $175 Ultimate Sprag (center). Notice the upgrade from four to six retainer screws and 16 instead of 12 rollers for greater load capacity. Recommended for all-out TorqueFlites, it's sold as PN K22961EVS-6.
A soft-bristle wire wheel...
A soft-bristle wire wheel is used to knock down the high spots, stake marks, and burs where the old race was pressed and staked into the case. This process smoothes the receiver cavity and eases the installation of the bolt-in race. Benoit warns, "Unless you are upgrading to a bolt-in sprag, never disturb the original race. Just leave it in place during the input shaft swap process and rebuild".
The bolt-in race is installed...
The bolt-in race is installed by gently pulling it down using bolts and stacked nuts to serve as spacers. Work in a criss-cross pattern to apply even force. Never use a hammer or brute force as you can crack the aluminum case.
This close-up shows the business...
This close-up shows the business end of the shift cable. It snaps into a pivoting sleeve that bolts to the valvebody rooster comb inside the transmission. Installation is a simple matter of pushing the cable through the case and into the sleeve. You'll hear it click past the lock spring once it is fully seated. Always make sure the rubber O-ring is fresh to prevent fluid leaks. Disconnecting the shift cable from the valvebody sleeve requires dropping the pan so you can access the retainer spring.
A quick, sure-fire method...
A quick, sure-fire method of getting correct shift cable adjustment is to have a helper fully depress the Neutral shift button inside the car while you manipulate the external adjuster ring. When the indicated arm (pen points) is aligned with the Neutral safety switch and the ring is flush against the case, you're done. A small lock bolt threads through the adjuster ring into the case to prevent disruption. If a reverse-pattern valvebody is used, remember to mark the shift buttons accordingly. The Neutral position remains the same regardless of valvebody type or modification.
The street manners of Max...
The street manners of Max Wedges and Race Hemis are compromised if you're stuck with a low-stall speed torque converter. Off-idle bogs and hiccups are par for the course unless you add some stall to mask the awkward transition from idle to power when those big quads open up. Thanks to the upgraded '67-'78 fine-spline input shaft and related parts shown in this story, your early B-Body's push-button TorqueFlite is ready to accept commonly available high-stall torque converters like this 10-inch unit. Drivability and off-the-line performance will improve immediately.