I'll second that. My edelbrock heads had significant runout in the seats, so I got a Hughes 5 angle valve job on them, and back cut the valves.
I ported them myself, following the recipe Steve Dulcich laid out over several MP and Car Craft articles. Pushrod pinch and exhaust port size are the major restrictions. A 408 has 48+ more cubes than what these heads were designed for.
I use a Hughes 218/228/112 0.565"/0.565" hydraulic roller cam, comp 918 beehive springs, Hughes 1.6:1 rockers. Eagle crank & I-beam rods. KB pistons. Total Seal rings. Performer RPM airgap intake.
I was hoping for 450hp/500ftlb at the crank. I was inspired by a series of torque monster 400cid builds in the magazines a few years ago. I ran 12.70's @ 107 with 727 trans and 2.76 gears. pretty torquey motor.