Clutch Bellhousing Questions

[Elwood]

I have two questions regarding the clutch bellhousings on our US spec M37s that hopefully someone with more experience can answer:

1. Here's an NOS bellhousing (casting number is 1269427-1, same as spec'd on page 53 of the TM9-1840A, June 1952):



And here's the bellhousing that was bolted to the T245A block (converted to 12v with a 6v starter and non-M37, six-bolt, thin flywheel) when I pulled it from my '54 M37 (casting number is 1269427, no "-1"):



The blue bellhousing looks a bit more robust (notice the extra ribs on the back), but I'm guessing that it's from a different vehicle, not an M37. Does anyone know (a) what vehicle this casting number was originally installed on, and (b) will it work with the 24v starter and thick M37 flywheel?

2. The military shop manuals don't seem to include any information about indexing the bellhousing to the block, but the Chrysler Six Cylinder Industrial Engines Maintenance and Parts Manual does include information on checking the lateral and radial runout of the crankshaft drive flange versus the rear opening and face of the bellhousing. Why would these measurements not be important to verify on the military engine/bellhousing?

[Monkey Man]

I'm no expert on the different bellhousings but measure up the mating surfaces from front to back and all clearances for the indexes, apetures and starter position and you should have your answer, also, Dodge parts such as this were a standard configuration on the later vehicles, I would think this was a philosophy from way back and applies to the earlier machines also.

MM

[jordankjcm]

I believe the "-1" dash one suffix is what is known as a "tooling revision number" or a "dash number" after the casting number. The tooling revision number, which indicates how many times the tooling (core molds) have been reconditioned back to the proper specifications or modified to include improvements. After so many "pours" the tooling gets worn and needs to be reshaped or reconditioned. They should have the same measurement specifications.

[Elwood]

Thanks, guys. I was thinking that the dash suffix might indicate backwards or forwards compatibility, but after some more research, I'm inclined to agree that it's related more to foundry operations.

I'm still trying to figure out why the industrial engine manual specifies bellhousing run-out tolerances, while the military manual does not.