I was just thinking as I was reading the title of this thread on the home page, If you replace small valve, small port, open chamber heads with closed chamber, big valve, big port heads it has got to be a very noticeable improvement.
Yes it's true. I personally know that a single 4-bbl, pump gas 451 with ported Edelbrock RPM heads can make 720-770+ horsepower. Pull...after pull...after pull...after pull...with a one pull peak of 786.9 HP.
