You need to consider as Dwane pointed out the seat material in an Indy head and the valves you choose to use. As for power you should find some replacing the valves and also likely more in a good valvejob in the new seats, if using an uncoated valve, IMO change the seats either way. Is the cost worth it? Thats a question only you can answer. Titianium valves come at a cost in money for sure but these days time can be an issue as well.