Did he say they're as good? I thought he was trying to say not to disregard them because they can be made to provide good street performance. Smaller valves, less flow and less compression can't be as good.I think reworked C1TE's can perform better than ECZ-C's and those were use during the 2nd most powerful year.
If yours used sodium filled valves, just use regular valves. I think it will require different valve guides to get it down to the regular size. That shouldn't be a big deal at the machine shop. Go ahead and install the bigger intake valve. It's not going to hurt. While they are posted, you're probably not going to need them, but it does kinda future proof it.