360 coming back together

If the porting job doesn't increase the low lift numbers, then the above equation is true.
Porting the head to flow big numbers above a cam lift of .500, the porting work is more likely wasted. I have been asked if porting a head for a cam of .600 lift and then getting a .500 lift cam would be a good move.

More likely, the answer is a big NO! Becaue of the added are in making the port larger, which is often the case, to get the bigger flow numbers kills the air and fuel speed that would be better to have with the smaller cam.

Now if you can port the head to flow a whooppping 300 cfm while maintaining a high port velocity of a milder port job and smaller window, your really in good shape.

Case in point is the magnum head. Smaller ports, high velocity in a small port. Win win win! This is why this head can work well on a 318 and a 360.
A X or J head with larger ports flowing less or equal will perform worse than the Magnum head for this reason. The X or J head will not pick up until that engine starts to spin fast. Not so great for the street daily driven rides.
(Though it may have a spot in a wild 318.)