Testing Yamaha 357cc Engines

[random1]

Hello All,
I'm writing to request help testing, evaluating Yamaha 4-Stroke 357cc engines. I happened upon several Yamaha 357cc Engines most of which look almost new. Is there any method to test (i.e. compression, etc) the basic engine health of the engines when the engines are not in the cart? I'd prefer not to remove the head or disassemble the engines. Does it make sense to attach a drill and spin the engines and test compression? My goal is to sell these engines and know the internals are somewhat healthy.

Thanks in advance for any ideas or pointers.
-randyb