I have actually been testing quite a lot lately. Usually 2-3 hours before work each morning. Most of my tests have been with the Speedmaster head and a 2.02 valve. For months I’ve been trying to make a 300 cfm port that does not nose over/back up at 0.500-0.600 lift. I finally hit a legitimate 300 yesterday with only a slight dip in the curve at 0.600 lift.
It sure would be nice to have PBR around to get some direction. I’m thankful for the posts that he left us. It’s amazing how many times I’ll learn something and then remember one of his posts, especially regarding the short turn. I go back to them frequently. He is missed for sure.
As far as your build goes, 400 hp from the 360 should be well within reach. If you go with the Speedmaster heads, get them bare and have a good valve job done, maybe even go to a 2.055 valve. I think SM makes the throat too large to begin with. On the bench this head likes an 88-89% throat. I think that would work better on the street than the 91-93% throat they come with.
On another note, I’ve got some 318 poly heads I’m excited about grinding on. I just wish there was more metal around the port. You’re a poly guy, right?