After we scored a complete...
After we scored a complete short-extension four-speed setup from a junked late-'70s 318 F-Body, plus a set of A-Body swing pedals at a swap meet, we were ready to work on our Dart. Find a good place to work; this'll take awhile. Get a set of good H/D high-lift jackstands and raise the car for working clearance. Next, the automatic comes out. This 727 was nice and strong, but there's nothing like banging gears with your right fist.
"Four On The Floor."
If there's anything that captures the soul of a pure, old-style musclecar, it's banging out shifts with a four-speed manual transmission. No doubt the Torqueflite is good, arguably the best automatic of the supercar era, but for all-out power-shifting brutality, that four-change took the prize. Perhaps it's that deeper level of mechanical connection that comes with hand-grabbing gears that can't be matched by a juice-shifted box. Like their automatics, Chrysler's A-833 manual transmissions were the best of the breed, designed from the start to survive on the strip behind the thinly disguised race engines the company was noted for. To quote the factory literature, "... it is still the strongest, most dependable, four-speed production transmission available in assembly-line built passenger cars."
Got a hankering for a cold chrome stick snaking up from the center of the floorboard yourself, but your Mopar left the factory a pedal short? The change can be made. Be forewarned, however, that this transformation is not for the weak of heart or mechanical ability. In fact, the MP Chassis Book warns, "The conversion of an automatic transmission car to a manual transmission is extremely complicated and not recommended." For purists of originality, such a swap may even be perceived as malfeasance, especially on a rare or historically significant vehicle.
That behind us, my modified daily driver '69 Dodge Dart Custom is neither rare nor historically significant, and it was already carrying a modified 727 TorqueFlite with a high-stall in place of the stock 904. Why mess with a good thing? You can make all the excuses you want about the better fuel economy, quicker times in the quarter, or available overdrive ratios-the truth is that the seduction of grabbing gears in a hot small-block Mopar was reason enough.
In reality, the list of what's needed to make the change is not that long: a pedal set; clutch linkage; clutch disc, pressure plate, and throwout bearing; the bellhousing and trans; a shifter and linkage; the floor tunnel hump; four-speed carpeting; and maybe a steering column. The tricky part is amassing the parts required, with the key being compatibility. For it to work, the four-speed tranny system has to have the right players on the team in your conversion. The clutch has to be the right size for the flywheel, the pedals have to be correct for the body type, the flywheel and tranny pilot have to fit the bellhousing, and the list goes on.
As you might guess, there were many variations; unfortunately too many to cover them for every application here. The best bet is to source the conversion pieces from a single compatible donor vehicle of the same body type, buy the pieces from a specialist such as Brewer's, or just know your four-speed stuff cold when shopping the boneyards and swap meets. The Mopar Chassis Book has an excellent chapter on four speeds that covers most of the parts variations you need to know if buying the conversion parts a-la-carte.
Inside, the front seat and...
Inside, the front seat and carpet have to come out for the tunnel mods. The pedals also need to be changed, and the column should be replaced or modified to give the correct look. Pulling the column gives working room down at the pedals.
The automatic's brake pedal...
The automatic's brake pedal needs to be disconnected from the brake pushrod by removing the special pushrod pivot bolt (arrow).
Under the hood, the brake...
Under the hood, the brake master cylinder, or power brake booster if so equipped, needs to be unbolted so the automatic trans pedal assembly can be removed. Inside, a few bolts are removed, and the whole pedal assembly can be pulled as a unit.
The auto-trans and manual-trans...
The auto-trans and manual-trans pedal assemblies are identical, except for the swing pedals themselves, and the over-center spring used with the four-speed assembly. The brackets are the same. As a result, the four-speed swing-pedal assembly was just bolted in place of the old one.
The flywheel needs to be balanced...
The flywheel needs to be balanced correctly for the engine application, either zero balanced for internally balanced engines such as 318s, or one of a number of externally-balanced units matching the balance requirements of various externally-balanced engines (440 Six Pack, cast crank 340s, all 360s, and so on). The junkyard clutch cover from the F-Body was in nice shape, so we just tossed a new clutch disc under it and bolted it up.
Underneath, the crank needs...
Underneath, the crank needs a pilot bushing installed to run a four-speed. Unfortunately, not all Mopar cranks were drilled or finish sized for the bushing. Cranks that are drilled, but not finish sized, will work if the O.D. of the bushing is turned down, or often with a NAPA 615-1033 undersize bushing made for unfinished cranks. Undrilled cranks can use the later Mopar bearing 53009180 which fits in the crank's torque converter hub register, though the nose of the trans' input shaft will need to be hacked off for clearance. Luckily, the Dart's '84 police 318's crank was drilled and sized for the regular pilot bushing. Knock it in with a proper driver.
A key mod in the conversion...
A key mod in the conversion is the tunnel hump. In the old days, these were cut out of original four-speed cars, but try finding one today. Thankfully, Sherman & Associates makes great reproduction humps for the A-Body (top) and pre '71 B-Body (lower) which makes the floor conversion a lot less painful.
The tunnel hump is first laid...
The tunnel hump is first laid over the floorpan and the outline is marked on the pan using a wide Sharpie. The hump isn't positively located, so just move it around for best fit. Notice the gap at the back of the hump. Because the hump is patterned to fit the late A-Body, early cars are left with a gap.
The floor pan is cut out well...
The floor pan is cut out well inside the marked lines, just enough to clear the tranny, and the trans is bolted into position. Important-Don't cut into the crossmember! Double-check the shifter location in the hole before finish-cutting the floor.