Taking it a bit further.... all US 2V heads have open chambers...4v heads are available in open chamber & closed chamber styles. If you hear about "Aussie" heads, they have the 2V ports, but a unique, smaller closed chamber & were actually used on the Australian 302C. Open vs. closed chamber can be (& has been) debated to death....either design can work if built correctly. Closed chamber heads have a "quench" area, the open chambers don't (strictly speaking). For all intents & purposes, Cleveland builders who are trying to make very serious power stick with CC heads (though the OC heads can do very well on the street). The aftermarket heads, whether 2V, "3V" (an in-between port size), or 4V, use closed chambers....though the chamber designs are all very different from Ford's original closed design. 2V ports are a little more street-friendly, BUT 4V heads can be made to work VERY well on street engines with a bit of thought & effort.
The Jalopy Journal
