Chevrolet Repair: 2000 chevy tahoe limited 350 5.7

Question
White smoke comes out,in two sparkplus presue is low n has gas or oil on them moto shakes n has a lightly clicking sound n motor also lost a lil. Power but over all runs good still why and i cant seem to find anyone to help me out they jst say u need new motor

Answer
It is hard to figure all of what your saying.From what I can figure it needs at simplest the heads to be taken off and corrected then back together with new head gaskets. The heads need to be accurately made strait . Made flat. The heads must be okay -the valves work right and they do not leak also. Good Luck Amigo