Both of my porters have retired. I'm looking for another.
But FWIW, these heads out of the box will support 670 hp out of a 449ci engine with a .700" lift cam. On a typical street 445, they will make 550 hp and 590 lb-ft with just a 231° intake lobe on a hydraulic roller, and make 15" of vacuum.
I know we made a big deal at the beginning when we first started using them about the flow backing up at .625-.650", but to be honest, I'm not really sure it puts a dent in anything.