Why is ther no formula to figure out port volume?

I guess what we should ask the original poster is what engine are you trying to build and get him in the right direction for what he needs.

Moper, I think that were both comming up with the same solutions but arriving at it differently. I sure don't want to confuse him. You and I understand it but he may not. Thats why I stated that maybe he should give me the info and or us so we can help him figure it out.

For instance on a race 318 .030 it shouldn't need any more than a 140 cc head port with a 1.78 intake valve and flow 240 cfm's this would be enough to turn the engine 6500 rpm's +. But would this head work on the street, maybe so but it would be very over kill for a street 318 regaurdless of over bore. According to my program a street 318 doesn't need any more port volume than 124-128 cc's and 205-215 cfm's of air. Basically a 302 head with gasket matching and bowl blending. Then I help the head out with a 1.60/1.625 exhaust valve, because why get it in if you can't get it out.