Splash lube: Has an oil slinger ran off the cam. The connecting rod has oil holes to capture oil for the bearings.
Pressure lube: Has an oil slinger ran off the cam (STILL NEEDED) and has an oil pump giving oil fed to the main bearing.
The connecting rod may have oil holes to capture oil for the bearings.
Full pressure lube: May or may not have a slinger(USE IF PRESENT) and has an oil pump feeding oil to the top main bearing
of motor and all the parts in between. Usually through the cam and a hollow crank. Oil is pumped through the connecting rod.
I have seen a single OHV with oiling through the crank, but do not have the number handy.