Muncie M21 (auto to manual un-conversion)

[Eric1970]

My 1970 longbed, step-side originally came with a 4-speed manual.
The previous owner installed a turbo 350, which I have now severely cracked.
I've been wanting to change it back to a four on the floor.

Does anyone have an idea of where I can find a remanufactured Muncie M21, preferably with a super case and mid iron plate?
(I've heard the super case and mid iron plate make it stronger;
Experience/opinions on this are welcome.

As I'm un-converting it, it is my understanding I'll need:
A bell housing
Flywheel (with number of teeth to match my starter)
A pressure plate
A clutch
Clutch fork, and a
Pilot bushing or bearing.

It was suggested I look for a donor truck to get the majority of the parts needed for un-converting it.

Fortunately, it looks like I'll have shop access to do the work.

Any ideas/insights into this project are most welcome.
This is the last moving part I need to replace.
After this, I can finally get to the body.

Thanks, all!