Speed Gems II Transmission Adapters




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Installation Instructions




  Install instructions for

Model A & B to Chev Automatic trans.


This kit will allow you to bolt up any of the Chevrolet automatic transmissions (700R4, 350 TH, 400 TH, 2004R, Powerglide, etc.) to the Model 'A' and Model 'B' motors.


Kit Contents:

      Adapter Plate

      Crank Adapter

      Flex Plate

      Torque Converter Drive Plate

      Starter Adapter Plate

      Mini High Torque Starter (this starter will only work

           with our kit.)

      Bolt Kit

We assume that the person installing this kit has a certain amount of mechanical aptitude and ability. It is not for the beginner. Make sure you clean all surfaces when mating these parts together. Always check bolt clearances. We try to make everything as simple as possible to help you, but the ultimate responsibility as to the assembly of the kit is up to the installer. Check and recheck as you go. We canít foresee every change or modification that could possibly occur in the building of a custom vehicle. Especially when we are dealing with 75-year-old motors.

A few common sense installation tips.

1. Install all bolts before tightening any in a given sequence.

2. Use loctite and torque bolts where applicable.

3. Donít over tighten bolts there is NO warranty on stripped threads.

4. Make sure all surfaces are clean, flat, parallel, etc. The #1 problem is not paying attention to detail.

A good start is to remove your existing starter and flywheel. You will be reusing the flywheel cover. Make sure the crankshaft is clean and no burrs. The new flywheel w/ring-gear and crank adapter supplied with this kit goes on next.

Along with the 2 crank dowel pins, the new flywheel also indexes on a machined lip on the crank adapter. Make sure that it is fitted onto the crank adapter locating area before bolting the whole thing together. Make sure that the assembly fits flush on the crankshaft. It is a tight fit over the dowel pins. You may have to tap it into place. Donít use a hammer. Use a rubber mallet or a piece of wood.  Install 2 bolts thru the crank adapter and flywheel to temporarily hold the flywheel and crank adapter in place. Now install the adapter plate to your original cast Model A flywheel cover with the supplied capscrews. The new adapter plate indexes the same as the original bellhousing. There is a machined lip that fits tightly into the flywheel cover. After this is done, remove the bolts previously installed to hold the crank adapter & flywheel. Install the triangular shaped plate that serves solely as a torque converter drive plate. Install the 4 -12 point ARP bolts. Torque to factory specs. The torque converter drive plate has two sets of holes for the torque converter. This allows you to use either of the two bolt circles that Chevrolet used from 1955 up to present day. Generally, the 400TH transmission and the 4L80-E use the larger bolt circle. All other Chev automatic transmissions use the smaller bolt circle.

Now install the starter adapter to the cast Model A flywheel cover. It only installs one way. You are now ready to bolt on the supplied starter. It also only bolts on one way.

You should now be able to bolt on any Chev V8 style automatic transmission with no modifications to the transmission or torque converter. This kit does not address the many other modifications necessary to get the automatic transmission into the stock Model A. It merely allows you to bolt the transmission to the engine.

Some of the other modifications that need to be addressed are: parking brake, manual brake linkage, torque tube rearend, crossmember, automatic shift linkage, cooler lines, etc. The transmission that I think works best with this setup is the 200/c transmission. It has the smallest overall case size and is very light. (about the same as the C4). It isnít an overdrive transmission, but it has a lockup torque converter which can be good for about 300 rpm at highway speeds.  It also has much better gear ratios than the 350th or the 400th, and is very reliable when built correctly. It would be wise to take into consideration how much horsepower your engine has before using an automatic trans. By nature, the front pump of the automatic transmission uses some available horsepower to run. If you are using a stock engine, youíll have very little horsepower left to drive the car. Removing the heavy stock flywheel also means less available torque at low RPMís. The stock flywheel delivered quite a bit of torque via inertia (rotational force). What Iím saying is that this kit works best with a modified engine. Any questions, call us at 763-767-4480.