So, there I am looking at the ET heads and I'm confused. The 265 seems to have the best low lift numbers (on a 4" bore) other that the 215. Adjusting for bore size (the 215 was tested on a 3.9, the rest on a 4.0), the 215 seems to be a match for everything up to .55 or .6.

I would have thought that the .100, .200, .300 numbers would have been strongest in the smaller sizes. They only seen to be in the 215. Based on the numbers the 225 looks weaker than all of the others.

What are the differences between the 215, 225, 240, 255, and 265?

Sidebar: In the 410cid Engine Builders Challenge (which looks at average power and torque from 2500 to 6500) builders seemed to use 180-220cc ports. Power peaks were in the low 6000s. Which seems like the target range for a hydraulic roller LSx.