Ok. Im just throwing this out there because this is what happened and found it a bit odd. But hey, everyday is journey i guess. Veh is as many know of as, Frankenstein. 63 GMC 2500 series chassis, 66 Chevy cab and clip, 55/59 9ft stepside bed. Loving it more and more everyday. Anyhow, today was the first day that this veh has made it to the interstate. Lol. All good for a min, the started an upgrade at about 50/55 mph kinda felt something wierd to say the least. Then down hill, all good. Flat, ok. Then started back up another grade and felt like starving for fuel. Got so bad, had to pull over. Slowed and pulled over to the berm. Running, idled, and reved fine. Got out, opened hood, nothing out of the ordinary. But i seen a glare of the oil in the oil bath through the slightest opening at the top where the air would enter the air cleaner. At that moment i remembered putting 10w30 in the air cleaner to the full mark as indicated. Had the carb apart twice, new pump and all back from there, so thought it was worth a try. Pulled the air cleaner housing off, put it on the pass floor, slamed the hood and proceeded up the berm. Yielded on to the roadway, at an upgrade to boot, and all was smooth sailing from there and the next 30 mile circle till home. I wont be using that oil/air filter again. Weather it was to much oil, wrong oil, or God know what, it aint going back on my truck. Morel of the story, Dont overlook whats right in front of you. You might just figure it out. Lol... Sometimes...