David Vizard - Which to prioritize - PORT FLOW or PORT VELOCITY?

But I think for most of us, that aren't bound by strict rules and highly competitive racing, the average performance guy. To build an engine with Slightly less inefficient HP is generally gonna be easier and less expensive to build.

A highly efficient 1.35-1.65 lbs-ft per cid is generally gonna be out of the range for most of us.

If you want 500-550 hp and torque with peak hp around 6000 rpms most don't think to build a highly efficient 360 to do it with only 220-240 cfms but a less efficient 408 with 275-300 cfms.

Even most mild engines would require less port volume than a 273/318 head has with more cfm then it generally does.

At Peak hp @ 5000 rpms these engine would need these port volumes and cfm to have optimal velocity, 273 = 99cc/167cfms, 318 = 115cc/195cfms, 360 = 130cc/220cfm, 408 = 147cc/250cfms so generally we would need to shrink the port while gaining cfm beyond most capabilities to have ideal velocities with a mild street engine.