Muncie Bell Housing Adapter Ring

Muncie Bell Housing Adapter

Good morning, and thanks for finding my Muncie Transmission Bell housing Adapter. This particular product came about as a personal need. I got one of the large pilot hole bell housings for my personal El Camino project and had my brother make an adapter ring for me. In the following years, it became apparent that others could benefit from this part as well. So, here it is.

Normally, I make the adapters to the exact theoretical diameters, plus a few thousandths of an inch on the outside diameter for a secure fit. The outer diameter is 5-1/8 inches and the inner diameter is 4-11/16 inches.

Please, verify that the pilot on the transmission fits into the adapter before and after you install it. It would be very frustrating to find that it is too small while trying to install the transmission under the car.
It will be several thousandths of an inch larger than the pilot on the transmission.
It will close up a little when it is installed into the bell housing. Now, this is not to say that you can ‘throw the transmission in from across the room’.

The Bell housing Adapter should slide in fairly easily, but, it is supposed to be a slight press fit.
You should not be able to push it into the bell housing with your fingers.
You could put the adapter in the freezer for a couple of hours to shrink it.
At the most, if they are a little too tight to suit you, lightly HAND sand the outer diameter and tap it in with a small hammer and a block of wood until it is flush with the outer surface of the bell housing.

There are several ways to secure the adapters.
What I did on mine, and what I recommend, is that you use a type of Loc-Tite specifically for retaining bearings on a shaft. Put a few drops on the outer dia of the adapter and install it as indicated above.
Then, after it sets, drill and tap 2 or 3 ¼-20 threaded holes at the mating hole intersection between the bell housing and the adapter. Put in a couple of set screws using the same Loc-Tite, and you’re set for life.

Before you bolt the bell housing to the engine, assemble the bell housing and transmission and verify that the transmission pilot goes into the Bell housing Adapter Ring. If it is too small, lightly sand the inside diameter of the adapter until it is a sliding fit.

As always, I guarantee everything that I make.
Absolutely no exceptions.

To order one or more of these items, please call 502-222-5764 from 8:45 AM till 4:00 PM eastern time Monday through Friday and give Linda your credit card information.
We have these in stock and ready to ship.  Price, delivered USPS is $38 each.
Thanks for looking.

Best of luck to you.


Dennis W. McLeod
Toolcraft Co., Inc.
shop 502-222-5764
Cell 502-558-1043
Bellhousing Adapter Rings ready for shipping

For V8 Chevrolet engines---------------------------since the VERY first Chevy 265 V8 in 1955, there are TWO sizes of bell housings. There are SEVERAL different bell housing configurations but there are ONLY TWO sizes---big and small. Each must be matched to its respective flywheel--again, big and small.
Starting with the first V8 in 1955, there was ONLY ONE flywheel/bell housing size----big. The big flywheel is 14in diameter with 168 teeth. That 14in flywheel will ONLY fit a BIG bell housing. In 1963, Chev introduced a smaller, 13in, 153 teeth flywheel AS WELL AS a smaller bell housing. There are SEVERAL small bell housings for the small flywheel. The 403 is the one which is about as common as dirt------------------and is the cheapest to buy--------------usually about $10-25 at swap meets. The 421 housing, which is essentially identical to 403, is a 1963 ONLY housing. What makes the 1963 421 housing unique is the hole in the rear of the housing where the tranny front bearing retainer fits. It is smaller than the hole in all other housings (why in God's green earth Chevy did this in 63 is anyone's guess). Another oddball small housing is the one for the 64-67 CheveIIe with a V8. It has the hole in the SIDE of the housing pointing down at an angle so that the throw out bearing fork doesn't cause any interference. Even though all of the above housings have a different configuration, they are still the SMALL housing for the SMALL flywheel. ALL the small bell housings are the full enclosure style. THE SMALL FLYWHEEL REQUIRES A STARTER THAT HAS A STRAIGHT ACROSS BOLT PATTERN FOR ATTACHING THE STARTER TO THE BOTTOM OF THE BLOCK.

The BIG flywheel (14in, 168 teeth) was first used beginning in 1955 on the first Chevy V8. The BIG flywheel can ONLY be used with a BIG bell housing. Over the years there have been several configurations of big bell housings, but they will all work with the big flywheel. The 55-62 (used on some trucks up to about 1970) bell housings were cast iron (except for 60-62 Vettes and 60-63 hi-perf 348 and 409 engines in cars which was alum) and they ALL had an open bottom with a stamped sheet metal pan. Then, in 1963, the full enclosure BIG aluminum housing was introduced. Again, there are several configurations of big housings, but the MOST common and cheapest is the 3899621 (commonly referred to as the 621) housing. The 3872444 is nearly a clone to the 621 and was mostly used on 66-67 Vettes with a BB, but some 66-7 Chevelle owners have reported original 444 housings on their SS396 cars. Later, there was a 464697 housing which is also a near clone to the 621 housing, plus it was also a service replacement for the 621. The 697 was listed in the parts books under TWO different part numbers, depending on the location of the hole for the ball stud for the throw out bearing fork. So, for the full enclosure, alum bell housing, there are basically 3 choices: 3872444 (translate VERY$$$$$$$$$$$$), 3899621 which is fairly common but prices are increasing for this one, and the 464697 which is not terribly common-----but for a Chevelle, it will only work if it is the version that has the hole for the ball stud in the "normal" position. VERY, VERY, VERY few people on the planet can immediately spot the difference between these three big bell housings because the diffferences (other than the casting numbers) are so minor. So, either of the three will work perfectly.

Big bell housings require a starter with a CAST IRON, STAGGERED bolt pattern for attaching the starter to the bottom of the block. Starters with an aluminum nose and the staggered bolt pattern will ONLY fit an automatic tranny. The starters for the 55-62 (up to 70 for some trucks) bell housings bolted directly to the bell housing, not the block. BUT, if you use a later block that has the threaded holes for mounting a block mounted starter, and you use an early iron housing (for example, installing a later 350 in a 55 Chevy and using the 55 iron bell housing), you can use the later, block mounted, iron nose, staggered bolt pattern starter instead of using the original style starter that bolted to the bell housing.

Now, one last thing about big bell housings. The full enclosure aluminum truck housing, 460486. This is a big housing, it fits a big flywheel, will accept an 11in clutch, and a tranny (such as a Muncie) bolts up to it just fine. BUT IF YOU USE ONE OF THESE TRUCK HOUSINGS YOU MUST HAVE AN ADAPTER RING! The reason is because it has a bigger rear hole than the pass car housings. This hole is what properly centers the tranny with the rear of the crankshaft, NOT the four bolts that attach the tranny to the rear of the bell housing!!!!

There are unscrupulous sellers at the swap meets that will sell one of these truck housings to unsuspecting buyers, but these truck housings are VERY easy to identify immediately from a car housing. See below for pictures. The truck housing has an EXTRA bulge around the bottom of the housing, whereas the car housings are just rounded (does that make sense).
Also, it is super easy to immediately identify the difference between a small and a big housing WITHOUT looking for a casting number! On the SMALL housings, both sides are straight and the bulge for the starter nose DOES NOT protrude beyond the side of the housing. On the BIG housings, the bulge for the starter nose protrudes approximately 1in beyond the side of the housing---regardless of whether it is a 55 iron or a 90 aluminum housing or a truck housing. ALL of the big housings have the starter nose bulge sticking out about 1in.


This piece of work was stolen from the Team Chevelle web site page. The author is a rather significant authority on the bell housing dilema that most of us face at one time or another. I thank him for his diligent research and make no assertion that any of this valuable information is my own work. Dennis W. McLeod
Small and Large Bellhousings