Allis chalmers M engine

[mschwartz]

Is the serial number stamped on the M engines? Not seeing it behind the carb or any other easy to see place. Picked up a couple engines and trying to figure out what I have. I see a casting date on the rear of the heads. Could the earlier 300 cubic inch motors be resleeved to become 318 or was there a crank difference? Thanks, Mike

 

[mschwartz]

After much cleaning I found serial numbers stamped into the pad below the oil fill tube. Looks like UMA 23210so I am guessing engine serial numbers include model U tractors and model M crawler tractors.