The gasket appears to be wrong on the passenger side only (the side with the oiling problem).

Then you should reevaluate the cooling issue.  The  temp sender is in the driver's side head and if coolant is flowing correctly on that side, then an overheating problem may not register on the gauge.  Get a laser thermometer, and with the engine up to normal operating temperature, check the rear, passenger's side head and block temperatures and compare them to similar locations on the driver's side.
Unless the person who assembled the engine also modified the gasket, thinking it was manufactured incorrectly, you have a cooling problem because of an incorrectly installed gasket.  The laser thermometer should show you that.



Lawrenceville, GA

Thanks Charlie, I will check on that this spring. I do have a laser thermometer so it should be fairly easy.