How to swap a newer trans without an adapter.
Please note: All reference to the 218 engines are for the US made, 23″ version. The Canadian 218 is a 25″ series.

Circa 1959, a bellhousing was used, mostly on the Dodge 230, that was the correct depth and had an useable mounting face for the NP230 and the A-833. The mounting depth is critical in the application due to the length of the input shafts. This bellhousing can be identified by the fact that it also has the v-8 block bolt pattern. Depending on the transmission selected there will very likely be a need to make modifications to the bearing retainer register interface as well as providing proper transmission mounting bolt hole locations.
This bell can be used with the attending transmission and not require any change to the rear axle since the e-brake was still on the transmission tailshaft. This bell, along with the flywheel and starter can be used on a Dodge 230 or any of the larger Chrysler and DeSoto flathead 6  engines. This bell can also be used on a Plymouth 208-218 but a 208/218 flywheel must be used. There will likely be a starter to flywheel engagement issue, due to the differences in crank flange dimensions, if a 230 flywheel is used on a 218. The starter to flywheel interface must be checked whenever mixing various flywheels and bellhousings on any of the flathead 6 engines.
The rear engine mounts found on this bellhousing may or may not be compatible with your existing mount locations.

Now, with an adapter, a word of caution.
Because of the many variables involved in a swap like this there will not be a simple, one size fits all, package. In addition to the different transmissions available, the flathead engines also have some variations in the thickness of and the amount the crankshaft flange extends from the block. I will need some specific details in this regard should you decide to order an adapter.

My adapter will mount any post-62 small block bellhousing, including the 3 speed (NP230 type), 4 speed  (A-833) and the newer 5 & 6 speed units.

Caution: The 208-218 engines have a different amount of crank flange projection as measured from the face of the block. Flywheel to starter engagement must be checked when swapping flywheels and bellhousings on the 208/218, as well as the larger sixes and eights. My block adapter is designed around the 230 and larger engines and special shims must be used when adapting a post-62 manual bell to the 208-218.

The typical, post-62, 4-speed passenger bellhousing requires the use of a 130 tooth flywheel but because we are dealing with the pre-62 engines the flywheel also requires the 8-bolt crank pattern. The 426Hemi is the most common source for this flywheel, however, some suppliers have limited inventory and others charge a kings ransom for their pieces. There are a couple of options: 1) Some of the early, pre-62, 146 tooth wheels can be turned down for a 130 t ring gear. This will then bolt direct to your crank, no flange adapter required. 2) A 172 t flywheel, 426H style, may be cut down and the 130 t gear installed. A flange adapter is required. 3) The 143 t flywheel as described below can be modified for the crank pattern and may be suitable for installing the 130t gear. A flange adapter is required.
A slightly different approach is to use the bellhousing from a van/pickup that is paired to the 143 tooth flywheel. This eliminates the need to install a smaller ring gear but the 143 t wheel must be modified for the crank flange.
A pre-62 146 tooth flywheel can be used, however there is a slight, but annoying difference in the overall diameter between the 143T and the 146T wheels. Although the late starter does not recognize the 3-tooth difference, it does see the difference in the 14.6″ diameter of the 143 and the 14.65″ diameter of the 146T wheel. If the 146T wheel is used then the starter must be moved about 0.040″ away from the ring-gear. This move will be required anytime the 146 tooth wheel is used in place of the 143 tooth wheel.
Now, with the van bell, although the flywheel may be easier to deal with, the trans bolt pattern must be modified. The pass car bolt pattern is not generally found on the van and pick-up bells unless it was equipped with the 3+1 overdrive transmission which is a variant of the A-833 4-speed.
NOTE. Regardless of which bell you choose, you must insure that the transmission front bearing retainer matches the registration hole in the bell. If the bearing retainer is too small then a machined ring can be pressed on to the retainer to match the bell (or, the ring can be secured in the bell), if the retainer is too big then the bell housing can be bored out to match.

In addition, this adapter also mounts the newer ‘one-piece’ and ‘two-piece’ trans/bell units. There are several variations of usable 5-speeds and one 6-speed. The ‘one-piece’ 6-speed is the Getrag 238, used in 2005-2008 Dakotas and Ram1500 trucks, in both 2 and 4 wheel drive.
Useable 5-speeds are found in Dakota and 1500 series trucks starting around 1986 (AX5) 1988 (AX15) (two-piece) or later NV series (one piece).
If you select a two-piece type (AX5, AX15), be sure to get everything you can from the donor truck (trans, bell, slave cyl, clutch arm, starter). These have a unique bolting pattern to the bell and are not compaible with other manual bellhousings. Suitable donors ‘can’ include the 4-cylinder engines as well as the Jeep 4.0 inline but you will then need to source a v-6/v-8 bellhousing. Depending on your locale, you might even find a complete truck with a useful trans…. Replacement clutch assemblies, if needed, are readily available.
The 5 and 6 gear units require a 143 tooth flywheel. There are three options for this needed wheel:
If you get your trans from a 3.7 v-6, or 4.7 v-8 you should also get the 8-bolt flywheel. Replacement flywheels are also available from parts houses like O’Rielly’s. This flywheel will require that you redrill the crank bolt pattern for the larger bolt circle that is common to the flathead 6 and pre-62 v-8 engines. If you do not want to modify a flywheel or buy a modified wheel then your next option will be a 146 tooth count flywheel from a pre-1962 flat 6 or v-8 application (same starter vs diameter differences as above). If your existing car (pre-1957) has a manual trans you will have this wheel. Special note: the oem flywheel on a 208/218 has an approximate 0.200″ thicker center to make up for the shorter crank flange extension. In 1957 the tooth count changed to 172.  Although there are 172 tooth count flywheels with the same mean diameter as the 146, the original starter pinion is considerably smaller to account for the change in tooth pitch. Starters designed for the 143 and 146 tooth count will not engage the 172 in proper fashion.
The last source for a usable wheel is a 426Hemi flywheel with the required 143 tooth count. The 146t wheel is a direct bolt-up to your crank; the 143 tooth wheel will require a crank flange adapter in addition to the block adapter, but the starter does not need to be moved as when the 146T wheel is used. If you do not have a 146t wheel but choose to use one be sure to get the attaching bolts as they are somewhat special. I have them in stock if needed. Also, please note that the 146 wheel can be found with either 4, 6 or all 8 holes drilled for the crankshaft. These are precision holes and should not be drilled ‘at home’. If desired, the pre-62 flywheel can be modified for conventional cap screws. When installed on a low rpm 208-218-230 engine the 4-bolt arrangement, while adequate, does not have a high margin of safety. Some truck applications will have very heavy flywheels, above 40 lbs, and can be machined down to a more useful 25-30 lb range.

So, what are the specifics?
The flywheel ‘may’ need minor modifications; new ring gear installed; or, new mounting bolt pattern drilled; and may need to be drilled for whatever pressure plate you choose.
The late starter is used as is when the 143 tooth ring-gear is used and will require slight modifications for use with the 146 tooth ring-gear.
The stock dust shield requires only very minimal trimming.

Are there any other ways to get around all of the fussing with the various flywheels and possible starter modifications?
Yes! If your engine is due for a rebuild then consider welding up the crank flange and machining it to duplicate the style of the post-62 v-8 with the 6-bolt flange. You now have access to a vast supply of very common flywheels and flexplates. If you need additional information on this just send a note through the contact page.

Additional Manual trans information: With regards to the post-1988 one and two-piece transmissions, there are a number of ‘look-alike’ units, be careful when swapping transmissions and bellhousings.

Input shafts lengths vary.

Shaft Lengths
AX5 = 7.5″
AX15 = 7.875″
Pre 1995 R150\R151 = 6.5″
1996 up Toyota R series = 7.5″
87-92 Turbo Supra R154 = 7.25″
Toyota W series = 6.5″
Toyota G series = 6.5″
AR5 = 8.2″
MA5 = 8.2″
NV3550 = 7.875″ (this is a one-piece trans/bell)
NV1500 = 8.6″ (this is a one-piece trans/bell)

The Jeep/Dodge AX15 5-speed, the Toyota R150F, R151F & R155F, the 87-92 Toyota Supra Turbo R154, the Isuzu AR5 and the Pontiac Solstice\Saturn Sky\Chevy Colorado\ GMC Canyon MA5 5-speeds all share the same case to bellhousing bolt pattern (Large Pattern). As such there are a number of possibilities that can be had when a 5-speed is desired.
Given the variations in shaft lengths, we need to consider where the splines are located in relationship to the clutch disc. If any of the trans and bells are swapped around the spline location must be checked. We can support a ‘short’ shaft and we can shorten a ‘long’ shaft but the splines are not moving.
If the NV1500 or NV3500, as used with one of the engines first listed above is available then it can be used and the same flywheel notes apply as for the Dak AX15.

Other considerations for swapping the late trans into an early car include, but may not be limited to the following, depending on exact car-engine-trans combination:
•The flathead 6 bellhousing may have part of the clutch and brake pedal pivot attached (dependant on make-model-year) and thus fabrication of a new pivot assembly will be required.   
• The original car/engine assembly will likely have mounts attached to the bellhousing.
• The new trans mount will be about a foot farther to the rear so a new crossmember will be required.
• Rear engine mounts should be fabricated so as to attach to the two bolts that secure the plate to the block on each side of the engine, however, the trans still needs to be supported.
• The late starter requires 12 volts. Please refer to the ‘Electrical’ section for additional information.
• You will no longer have an parking/emergency brake. The common fix is to replace the rear axle. Suitable replacement units can be found by comparing the width of the wheel mounting surfaces.

At this point you also have the option of using either drum or disc brakes, depending on whether or not you install disc brakes on the front.
Check out these sites:

Disc Brake swap kits for 30’s-60’s Mopar
Mopar axle information.
General axle dimensional data, all makes.

Spring pads are readily available for welding to the new axle housing.
A new cable will be required to connect the parking brake actuator to the axle.
A new driveshaft is required. It is a good idea to obtain the driveshaft from the car/truck that you get the trans from. Again depending on vehicle specifics, the final shaft requirements may be that of a longer or shorter unit than the donor, and a new universal joint may be required to mate to the axle.

These guidelines are not particular to my adapter package. All of these will be required of any trans swap.