No, it has 12 individual ports, hence the name 12 port head. It was originally designed by Frank Duggan in Australia in the mid-1960's as a replacement performance head for the Chevy 250/292 engines. He latter partnered with Kay Sissell in the US that owned Sissell Automotive. Several upgrades and versions were produced through the years. The patterns I purchased came from Joe Deppe, who tried to also partner with Sissell in the 1970's, but a disagreement between them left Sissell and Deppe with their own patterns for the cylinder head.
My heads routinely would flow in the 330 CFM range, with the best being just above 340 CFM. Mike Kirby, the owner of Sissell Automotive after Kay passed away, had a solid head, had one CNC ported the flowed 400 CFM. I'll I dig some pics up of the heads....