Chunk out of block

it looks as though the #5 & #6 gave out due to oil lose which is usually the case with the way those two are oiled from the #4 main. the oil mod to the rockers may surely help by give that main and rods better oil pressure and supply. the mod takes the rocker oil off the lifter supply bore and not the #4 bearing keeping the all the oil on the main and rods.