Compression ratio vs Porting

Well, I'm a little confused then. Although I haven't opened the link yet. But I thought the stock CR for a LA318 was around 8.5 stock. And even higher before 1968? Maybe I'm wrong.

http://www.allpar.com/mopar/318.html

That link should be to stock 318 CR.

And I figured, adding the swirl heads with small combustion chambers would help raise that?