1.The FAQ does not have valve sizes in the head section.
2. Could not find anything that mentions valves for a K motor searching "valve size"
3. After googling, I found this:
http://www.toymods.org.au/forums/showthread.php?t=4365
valves, rockers, rocker shafts and rocke towers will change between the different heads.
If it had been covered better I would see it as being a waste of a thread but since there is SFA on it give him a break.