Tim,
Thanks - great link. That wasn't me ('twas "John Teee"). There's another "JT" on here competing for the moniker. Ha!
Anyways, I'll have to study that and see what's available. Replacing just the valves would be easiest, and I might have to change to a different keeper and spring retainer, but anything avoiding more machining is preferable. Even though my buddy down the street has a machine shop and available at my disposal...I will ask him about the bronze liners.
On that topic, I might like that idea because bronze has very good wear properties...a lot of european makes have all-bronze guides.
I did do some late night searchin on SBI's online catalog and found these:
Potential replacement:
http://www.sbi-e-catalog.com/PartDetail.aspx?PartNumber=01193+3&PartType=Valves
These look like they'll need some lathe work to cut the relief area just up from the tip.
OEM valves (for comparison)
http://www.sbi-e-catalog.com/PartDetail.aspx?PartNumber=00298&PartType=Valves