My adapter will mount any post-62 small block bellhousing, including the 3 speed (NP230 type) and 4 speed boxes (A-833).
The typical post-1962 4-speed passenger bellhousing requires the use of a 130 tooth flywheel. Bellhousings used on the LA engine in the mid-late 1970’s and into the 1980’s, in pickups and vans, used a 143 tooth flywheel and corresponding bellhousing. For the pre-62 engines, the flywheel 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. Or, a pre-62 146 tooth flywheel can be used as is, no modifications. The late starter does not recognize the 3-tooth difference, however, the position of the starter must be moved away from the crank centerline by about 0.050″ to accommodate the ever-so-slightly larger OD of the 146 tooth wheel. See text and photos under “Adapter Photos” tab.
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 bell unless it was equipped with the A-833 Overdrive transmission. The difference at this point is that the OD trans has a large front bearing retainer.
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, 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’ 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 wd.
Usable 5-speeds are found in Dakota and 1500 series trucks starting around 1986 (AX5) 1988 (AX15) (two-piece) or later NV series.
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 compatible 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 (VIN ‘K’, 2002 – 2012 Dakota, Ram1500), or 4.7 v-8 you should also get the 8-bolt flywheel. The flywheel will have part number 53020688AB cast into the back side. There may be other flywheels that will interchange but this is the only one verified. New replacement flywheels are also available from some parts houses and the wrecking-yard side of things should also have them available. This flywheel will require modifications. 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. If your existing pre-1957 car has a manual trans you will have this wheel. The last source for a usable wheel is a 426Hemi flywheel with the required 143 tooth count. The starter will not recognize the 3 tooth count difference between wheels.
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. 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. If you have a need to add holes for your specific project, note that these are precision holes and should not be drilled ‘at home’.
NOTE: The 146T flywheel requires a slight starter modification to allow the stock starter to engage the ring gear since the 146T flywheel is slightly larger in OD than the 143T unit. See text and photos under ‘Adapter Photos’ tab.
Special Note:
When installed on a low rpm 208-218-230 engine the 4-bolt arrangement, while adequate, does not have a high margin of safety. Also, note that some truck applications will have very heavy flywheels, above 40 lbs, and generally, they can be machined down to a more useful 25-30 lb range.
Truck flywheels will usually have either 6 or 8 attaching bolts.
If desired, the pre-62 flywheel can be modified for conventional cap screws and these holes are not required to be as precise as the pre-62 oem design. Specific details available on request.
…last thoughts on flywheels….or, how to make a useful change…
The flange on the crank can be welded up and machined to copy the dimensions of the late model A-LA-B-RB crank flange and by doing so, you now have access to the more plentiful, and infinitely cheaper, 6-bolt flywheels and flexplates. Although not an inexpensive modification, it compares favorably, overall, with the high cost of, and sometimes difficult to source, LateHemi parts.
As far as the adapter package is concerned, the flywheel is the only part that you ‘may’ need to deal with. The late starter is used as is and the dust shield requires only very minimal trimming.
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.
If your eyes have fully glazed over and you need help sorting out this flywheel info just give a call or send us a note through the Contact page.