I have a 66 W300. The truck sat for a long time before coming back to life. The motor was running fine, but with a noisey lifter. Now it starts and idles but when you step on the gas it bogs, sometimes spits in the carb or the exhaust. New plugs points wires cap roter and adjustments are good. Oil and filter change. No smoke or internal engine noise when running. Question! Could it be that due to the age (47 years) of the hydraulic lifters that they have weak internal springs and due to this that the valves are not opening properly? Has anyone ever dealt with a similar Problem with the 318 poly? There is a lot of experience out there maybey someone has a similar problem and resolved it. Thanks, Jim.