WHERE IS THE MODEL # LOCATED AT ON A CRAFTSMAN OILLESS AIR COMPRESSOR PUMP

SOURCE: Craftsman Air Compressor

piston seal problem for sure

SOURCE: i have a 33g craftsmans air compressor oilless

have a 26 gallon air compressor , changed regulator switch but it still wont shut off

SOURCE: Craftsman 3.5 hp portable air compressor keeps blowin head gasket

I would say the head or block is warped. Use Majic Marker to cover the mating surfaces , the head can be rubbed on a flat surface like a cast iron table saw to find the high spots, or the head can be rubbed on the block.
Careful work with a good flat file will remove the high spots.
The torque value sounds low even for an aluminum block, you could check with a small engine shop to get their opinion.

SOURCE: How do i remove the air pump assembly off my

It is in fact bolted directly to the motor. You should be able to do any repairs necessary without removing the pump from the motor. I am not sure of the set up of that motor. I'm not sure if undoing that plate will also remove that side of the motor. (Something you probably don't want to do.) If you see other screws or bolts under the plate I would assume that you are safe to remove the pump plate from the motor.

SOURCE: I have a craftsman oilless air compresser that

Are you certain you are getting the proper replacement? You may want to do a physical measurement on the bore and stroke.