[Woodz428]

It is the pin end that needs to be considered. I'm pretty certain that the M/400 have larger diameter pins than the Cleveland/Windsor. If you plan on busing them, that would take care of the diameter variation but the pistons would need be compatible with pin locks.
Rod journal sizes are the same, as are mains but pistons configuration is where you may have problems. Of course these type of problems are easily corrected with $$. It may be cheaper to have the pistons opened to the M/400 pin size and retain pressfit rods.