If your engine needs this special drilled bolt for the oil to get up to the rocker assembly and it was just rebuilt, chances are that the drilled bolt got installed in a different location on the head. I would remove all the long head bolts one at a time to see if it has been installed in a different location. Just retorque them to 90-95 ft-lbs (with oil) as you go. There is no problem doing this, since you are supposed to do this after you run the engine for the first time after a rebuild along with adjusting the valve lash. I have a 261 block with a 235 head and I was just looking in the hole where this drilled head bolt would be installed next to the oil tube (by the way I do not have a drilled head bolt. I looked for this special bolt the last time this drilled head-bolt topic came up on this forum.) from what I saw there is hole approximately 1/2" below the head surface inside the bolt hole perpendicular to lifter side of block. The oil tube hole comes up on the other side the same head bolt hole, so it looks like the oil flows around the unthreaded portion of the head bolt to get to the rocker oil tube. With the side cover removed on my 261 you can see a raised channel in the casting where the oil flows up through the block and into the head. It would seem to me if you had to drill a head bolt to get oil to the rockers that you would not have this raised oil channel, since apparently the oil channel is directly below the drilled head bolt. This drilled head bolt system seems like a bandaid fix to an engineering error if you asked me.
