Thanks aero! Looked that up and learned a lot today. However I could not find a calculator to solve hydraulic diameter for ovals like the hemi port. Lots of formulas to calculate it though. I did find a table for squared corner rectangles. 1.5 x 2 and that was a 1.71 round pipe. I'm going to work on this some as tonight's busy stuff. I'm going to draw up the port and see what happens when measured true instead of the angled cross section. Where's my scientific calculator?