oil temp hit 260 degrees , whats the best synethic oil

What RPM were you pulling? If you happen to be lugging the motor it will get hot. Best thing you could have done then is change gears and let the motor rev. Turn off your AC also to help reduce load. All motor oils are made to a certain standard so brand is kind of irrelivant. Your owners manual spells out the correct oil spec for your motor. It generally also gives grade recomendations for normal and extreme conditions. When summer towing fill to the extreme specs and go.