If youre spending $$$ on the head, why not do the big valves and lump ports at the same time? Sounds like all you need is that and a cam and youre good for the 1/8 mile.
What times/MPH are you running now? Trans/Rear/Exhaust?
As far as hardened seats, I guess it wouldn't hurt, but of all our family fleet of Ford&Chev engines, I have never seen one pound the valves in unless it was in a hard working truck or a 100,000+ mile engine. For a typical hobby car that will see 10,000-20,000 miles, I wouldn't worry about it- especially if there is any risk of hitting water cutting to put the seat in!
