70K on brazilian parts? WOW
btw reez, the 50K mile renewing of the exhaust valves are due to the original valve guide material being too soft and causing high oil consumption, get a set of guides cut from heavy phosphor bronze material (lathe guys in Pakistan know it as "oil waale guide") Mostly used in industrial engines.
If the original valve's margin is acceptable save yourself some money. If you need some valves ask some pro engine lathe workers to cut you a set of valves from big industrial engine valves.
