question. i have a 84 1/2 ton 4x4, with a chevy 400 small block. started to see a drop in oil pressure over the last month. did a compression test and found good #'s in all cylinders, but was only getting about 5 psi tops in the #1 cylinder, tried putting a little oil in there and still didnt get more than 5 psi, what could be the problem? havent heard any knocking. please help!