Roller lifters A engine
The simplest way would have been to get the lifters that you don't have to block the passages with. They are making them for mopars now. They have been out for a couple of years now, put some in a 360 block with only gringing in the valley for lifter retainer clearence and they worked just fine without any other modifications. Crane cams, and Doug Hebert has them.
BJR Racing