I used shell rotella oil.Today I looked at the pcv valve.The previous owner had tje vacuum lined reduced down to a pencil size vacuum line and plumbed into a very small port at the front of the carb.This port was below the throttle blades so it probably wasnt full manifold vacuum but I didnt check.I ran the line to the rear of the carb where it belongs.Hopefully that helps.P.S. we have been driving it to work-25 miles one way.