Like you say, I worked into the VE backwards. The peak horsepower rpm is 8,400 as an educated guess. The intake flow is 212 CFM at maximum cam lift and 28 inches. The engine BHP with this is 115.5 in the "Average" category. That is about 104 rear wheel BHP which is realistic, with a 110.25% VE.
The intake valves go into curtain choke at 8,964 rpm and the exhaust valves at 8,374 rpm. The rev limiter is at 9,000 so I want a bit more flow through the exhaust valve curtains.
The program was run again with 2mm larger exhaust valves. The exhaust valves curtain choke rpm went up to 9,011 rpm. Now the curtain choke rpm's for both intake and exhaust valves are near the rev limit.
The program says I need a minimum intake flow of 228 CFM at maximum cam lift. The 212 I have now is not enough. The program says I need 172 cfm exhaust flow at max cam lift. I have 183 now.
The bowls around the intake valves are poorly shaped. I asked the machinist to clean them up. I am pretty confident that will bring the intake port flow up to what I need. The curtain choke rpm seems OK so I will stay with the 2mm larger intake valves I have now.
The exhaust valves have me confused. They seem to work OK now based on flow test results. The curtain area is a bit small based on calculations, so I asked him to put in some that are 2mm oversize. They are standard size now.
I used PipeMax for this, not EnginePro. PipeMax seems to work best for giving me realistic results although there are hundreds of numbers on these printouts and I only know what half of them mean.