65 Barracuda 318 Rebuild, Cam, timing, lifters maybe a kit?

The ports flow not necessarily the chambers. Yes I would agree that a 9.5/1 318 will make more higher rpm power with 340/360 heads. (Open chamber)
They have larger valves and ports. I bet a closed chamber 302 head will out power a open chamber 318 head if both are built with the same compression.