I'm working on a 440. Stock manifolds, 440 Stealth heads, Comp Cams XE262H-10 cam and lifters, Comp Cams Ultra Pro Magnum adjustable roller rockers. I need shorter pushrods- 9.100", which I ordered from Smith Bros. They came today, and unfortunately, are drilled for oil-thru. I saw posts here that they would drop my oil pressure. If so, is there anything I can do besides return them and order custom? With the Comp Cams lifters, do they indeed drop the oil pressure?