This morning I walked into the garage and looked right at the LS3 oil pan and it hit me. There was no provision for a dipstick tube. The LS2 dipstick goes into the side of the pan. I was really sweating it for a minute. I call my friend Tyree and he told me that the provision was in the side of the block just ahead of the starter. It looks like a very small freeze plug. I knocked it in about three seconds and installed the tube.
Based on my experiences modifying various cars over the years, going from block hugger headers to longtubes, gaining 20whp is on the upper end of expectations.