Trends come and go, clothing, hairstyles, music, and architecture are always changing. It's probably safe to say that a large group of ROD & CUSTOM readers, young or old, tend to wrap their lives around trends and fashions that date back at least 3 decades or more. The one thing that unites all of us, even those who lead a seemingly normal life, is our fascination with that part of industrial design that concerns transportation. Even so, we still have our own kinds of trends and even fashion rules.
Despite the different camps within our subculture, there are many things we agree on, and the early hemi is one of them. Though the hemi has had its periods of waning popularity, it was one of the major players in the history of the hot rod ballgame. Countless records at El Mirage, Bonneville, and the digs have been and are still being made by these engines or their modern clones. The last decade's rise of interest in traditional hot rods has brought the early hemis out of the scrapyards and scrapbooks as the coolest engine for any fashionable rod. Aftermarket companies that have been around since the beginning are still making hemi goodies, and new companies are filling the gaps with new parts for an engine that was once considered obsolete.
As much as we all love the hemi, some of us enthusiasts would like to have an easier time accommodating the beast in our cars. Back in the day, we'd just open up our mail-order catalog from Newhouse, Honest Charley, or Almquist and we'd find engine mounts, speed equipment, and tranny adapters out the proverbial wazoo. Doing this swap today isn't so easy. Even if we had access to the stuff in the old catalogs, the transmissions the adapters were made for are almost as hard to find as a $50 Deuce firewall. For the dedicated hardcore, years and dollars can be spent tracking the right adapter and then a rebuildable '37 LaSalle manual box, plus the right flywheel, clutch, and other stuff to utilize it.
For the rest of us, we want a reliable, modern, automatic transmission that can handle whatever horsepower level we manage to squeeze out of our early hemi. This is now possible thanks to John Winters, Sr., of J.W. Performance Transmissions. The J.W. crew has been making street and race automatic transmissions for 27 years, and along the way has been asked to marry up all sorts of engine-to-transmission combinations (some combos make sense; others are off-the-wall.)
An engine-to-transmission adapter has to be a very precise piece to result in a drivetrain that isn't plagued with annoying and potentially dangerous vibrations. But it's not economically feasible to make a zillion different adapters for every obscure swap. Then John Winters had a flash of brilliance one day. What if all transmissions had a removable bellhousing that would make the adaptation process easier. Problem is virtually all modern automatic transmissions have a bellhousing that is an integral part of the case.
Having spent as long as he has dissecting automatic trannys, John pondered that one element all the transmissions had in common was the front pump, which was bolted to the front face of the main case with a mounting surface machined perpendicular to the shaft of the transmission. This seemed like the perfect place to engineer some sort of trans-to-engine adapter. John reasoned that he could make a nearly universal bellhousing that could be bolted to the transmission using a set of extra-long front pump bolts. There were enough bolt holes there to make a bulletproof connection to a part of the case that has a perfectly-machined reference plane. The bellhousing he came up with he called the "UltraBell" and the innovation earned him a U.S. patent.
The basic premise is this: the stock bellhousing on the front of the case is removed, and the UltraBell is bolted over the front pump. The engine side of the bell is cast with a thick flange at the engine side, which is drilled with the engine's bolt pattern. To utilize the same transmission on many engines with this type of bellhousing requires only a change at the engine side, where the foundry pattern is changed in shape to accommodate different block bolt patterns. Likewise, if J.W. already has a pattern for the type of engine, it isn't that difficult to change the pattern and machine the other end to adapt to another transmission's pump.
Making engine-to-transmission adaptations takes more than just good machining skills though; experience is critical. When the J.W. crew ran across a '40 Ford that was having drivetrain vibration problems with its early hemi backed by a Turbo 350, they knew they could do a better job. They attacked the problem and created a complete package for the early hemi that includes the UltraBell, a block plate, a crank adapter, hardware, complete instructions and even a special flywheel.
All of the early hemis (although they have their own marque-specific peculiarities) have a common bellhousing and rear-crankshaft-flange bolt pattern, which means that the J. W. package will fit your application regardless of displacement (241 all the way to 392) and whether it's a '51-58 Chrysler, '53-57 Dodge, or '52-57 DeSoto.
Because of the way the original Mopar bellhousings were attached to the early hemis (with an inside flange at the front) you couldn't take off the transmission without first removing the flywheel, which was a pain. J.W. solved this problem when they designed the hemi UltraBell by using an adapter plate between the UltraBell and the hemi block. Now you can remove or install the new automatic of your choice without complications.
As if the benefit of using a modern high-performance transmission behind your hemi wasn't good news enough, it also lightens up that big hunk of iron. Original starters for early hemis aren't easy to find, and the local auto parts store as been out of rebuilds since before you were born, so Mr. Winters designed his package to take a standard late-model Chrysler starter like you would use for a Torqueflite. Not only is this starter available everywhere, it's considerably lighter. J.W. Transmissions also makes a new flywheel for the early hemi, with the correct ring gear tooth count to mate with the late-model starter motor.
The installation is pretty straightforward, once the old bellhousing and flywheel are off the engine, the pilot bushing in the end of the crank is removed (if your engine had been last used with a manual trans). The J. W. plate is bolted to the block, where it locates precisely on the stock dowel pins. The early hemi is the only UltraBell application where an adapter plate is needed, and it's because of the funky way the stock bellhousing was mounted, and it gets rid of the old starter. Basically, the plate allows the J.W. bellhousing to be bigger than the block's bolt-pattern, accommodating the bigger ring gear flywheel needed to match the smaller gear on the late-model starter.
With all the other weight-saving parts you can get now for an old hemi, you can get the behemoth's weight down to something near a big-block Chevy. If you have raised compression in your hemi (and who hasn't?), you'll also appreciate the late-model starter for its improved cranking energy.
Before mounting the SFI-approved J.W. flywheel, the stock bolt holes in the back of the crank need to be tapped all the way through to 1/2-inch-20 threads for the new, high-strength bolts (old hemis had studs at the back of the crank). Handling the job of centering the new flywheel on the crankshaft is a J. W. piece of aluminum that taps into the bore on the crank. In the old days, those studs on the back of the crank kept the flywheel centered. Despite all the old hemi cranks having the same bolt pattern, there are two different internal diameters here, 1.945 and 1.855 inches. J.W. will supply you the crank sleeve/adapter when you give them the measurement of your crankshaft. The second purpose of the sleeve/adapter is to provide a concentric register for the new GM converter to align with during installation, and is important to prevent vibrations.
The hemi UltraBell can be ordered to fit a TH350, TH400, or Powerglide. What you have to do next sounds like a "radical bell-ectomy" but taking off the stock bellhousing from your transmission shouldn't scare you. Complete details and measurements are included with the UltraBell kit, and the deed can be done with a Bridgeport, reciprocating saw or an air tool with a cutoff wheel. The bulk of the housing is taken off on the first pass, leaving a small amount for a die grinder to finish off for a nice, clean edge. The cut doesn't have to be perfect (just don't let the blade wander into the pan rail or top of the front pump).
You can mask off the front pump and input shaft with duct tape and plastic during this procedure, but there's no need to disassemble the whole enchilada. Once you've done the obligatory post-op cleanup, you can remove the front pump bolts, push the UltraBell over your trans, and bolt it down using the high-strength Allen bolts supplied.
The engine-plate part of this package not only registers on the engine's dowel pins, but also has dowel pins of its own, onto which the UltraBell-equipped transmission can now register. Installation of the transmission and converter now follows standard mechanic's practices and proceeds just like this was an ordinary engine, not a legendary hemi. One other aspect of the conversion is that you can't use the stock 12-inch-diameter converter. To fit inside the UltraBell, you need a converter that is 11 inches or less with a standard GM 10 3/4-inch bolt circle.
So if you want those wide valve covers in your car, enough that you would cut holes in your hood side panels (that is if you'd even put a hood over such a classic engine) then the J.W. UltraBell may be just what you're looking for.
This J. W. Performance Transmissions...
This J. W. Performance Transmissions kit works for all early hemis, adapting several different GM automatics with a special flywheel, adapter plate, bellhousing and crank-sleeve adapter.
Here's a completed hookup...
Here's a completed hookup on an early hemi, showing how the UltraBell allows the use of a late-model Chrysler starter that's both lightweight and easy to find.
The CNC-machined adapter plate...
The CNC-machined adapter plate mounts on the block first. Use of the plate (used on the early hemi only) permits the bigger flywheel needed for the late starter and properly centering the trans.
Exacting registration is everything...
Exacting registration is everything when swapping transmissions. The plate registers on the stock hemi dowel pins (A) and then is secured to the block with countersunk Allen bolts (B). The crank-sleeve adapter can be tapped into the back of the hemi crankshaft with a soft mallet.
Note that the crankshaft has...
Note that the crankshaft has had the original studs removed and the holes tapped for 1/2-inch-20 threads. The internal size of the crank-sleeve adapter is important because it registers the snout of the GM converter properly.
The new flywheel is tapped...
The new flywheel is tapped onto the crank (centering on the crank-sleeve adapter), then new bolts are torqued in sequence. The flywheel is chrome-moly steel (SFI-approved) and has the 130 teeth on the ring gear to mate with the late-model Chrysler starter.
Here's the early hemi UltraBell...
Here's the early hemi UltraBell bolted in place on the block and adapter plate with Allen bolts around the perimeter. For an actual installation, the bell would have been mounted onto the transmission when bolted to the engine.
At J.W. Performance Transmissions,...
At J.W. Performance Transmissions, they cut stock bellhousings off on the milling machine, but UltraBell instructions show how to do this at home with a Sawzall on a fully-assembled transmission. The UltraBell locates on the front pump, not the case, so the perfection of your cut doesn't affect swap's alignment or operation.
Although this particular UltraBell...
Although this particular UltraBell is for a wedge motor with Torqueflite, this photo shows how a transmission looks after the conversion. The new 'Bell actually strengthens the transmission's case enough to act as an SFI-rated flywheel shield.