sorry so long, not as sharp as i use to be, my son n law bought a 71 rr 383, big big can and no coverter(dies when put in gear)heads shaved with shims under rockers, so we ordered a 284 cam, bought a set of rebuit 906 heads from indy( i know).yesterday i took it apart and sure enough shimmed, pass side rocker shaft holes was at the top(upside down), and i noticed 15 0f the push rods have holes thru them like chevys, motor was very clean, got it back together and set the rpm,s @ 3500 for 15 minutes, then dropped it to 950. noticed it had 10 psi oil pressure(aftermarket mech gauge) don,t know what it was before we took it apart, racing eng it moves very little, would these open push rods cause this? and what kelp it from blowing up? i,ve only saw solid push rods in stock eng, again sorry but any help needed