NO thermactor passages. I just removed the diverter valve and ran the smog pump straight to the cats. The "p" heads burn so much cleaner that you really don't need it.
One sure fire way to tell is the valve size. Standard GT-40 heads are of the 1.84 intake and 1.54 exhaust variety as the GT-40P heads are of the 1.84 intake and smaller 1.42 exhaust variety.