if your rods are like the middle ones, they are an aftermarket Cap screw rod. You shouldn't have to grind on the bolts, its the back side of the rods that will hit the cam. As for grinding on the front of the block for Timing gear clearance, That is normal. the area above the cam gear where the oil plug is hits those Double chains often. I have had to clearance some of those after a balance. I cant tell that they were ever ground on. Didnt seem to upset the balance at all.