With a 408, between those two heads, I'd go with the 210cc runners. You're feeding 'big block' cubic inches through small block heads... so it's hard to go too big.
Plus, the bigger/better the heads, the less cam duration you need to adequately feed it.
I'd go with the Performer RPM or the Performer RPM Air-Gap on that engine. Add headers and at least a 2-1/2" exhaust with nice 'see through' mufflers and mandrel bent tail pipes... and you're off to a great start!
Good Luck!
Plus, the bigger/better the heads, the less cam duration you need to adequately feed it.
I'd go with the Performer RPM or the Performer RPM Air-Gap on that engine. Add headers and at least a 2-1/2" exhaust with nice 'see through' mufflers and mandrel bent tail pipes... and you're off to a great start!
Good Luck!