Panic, This is somewhat OT but I'll ask anyway.
I'm building a 175 ci four cylinder. I want to run a pair of Zenith 28s on it. They have replaceable venturies that are available in 32mm, 30mm ,29mm, & 24mm. The pair I have were taken from a GMC small port Edumonds intake with linkage so I assume they were run as a pair likely on a 248 or 270. They currently have 30mm venturies. I'm trying to decide if they need to be changed. My use of you rough approximations come up with 224cfm to 265cfm @1.5" Hg based on your 235 & 261 calculations. Now I need to figure which venturies will do that.
