Valve Guides for Race Engines
 

It doesn't seem as if there are many non-standard Valve Guides around for use in 911 engines.

Is it worth making guides in Colsibro or similar or are are standard guides good at 8000rpm +

I go with technical improvements over the years.
When our babies were born (first designed) the factory probably used the best quality and metalurgy available.
Now...30 or more years later...perhaps there are better alternatives.
Silicon Bronze....Magnesium Bronze Alloys....embedded silicon sleeves....Teflon particles....Helical silicon sleeves....all sorts of new goodies available.
The new stuff can be long lasting...or better lubricated...or tighter on the stem perhaps (requiring less oil).
For your engine...you must decide.
Contact some manufacturers of replacement guides and ask.
Bob

just use the latest over-counter parts

after all - a race engine is only good for a few thousand track miles at 8000 rpm

& then you get to do it all over again

and the next time it is apart - check the clearances & see if they wore out