Has anybody put valves w 5/16/8mm stems in BB RPM heads?

I haven't been able to find anything here, but since smaller valve stems is a trend, just curious if anybody's tried it out.

Edelbrock lists 11/32" valves as standard. I am sure you could find a 5/16" valve in the right length. It would require fitting new valve guides. Sounds like a lot of work and expense to gain (lose) 1/32".

Recently changed my intakes to improve geometry.Bought a set of Manley severe duty,the stems were .010.Had to return them and get Ferrea valves because all my stuff has a .008 stems & guides.
What does your guide measure?

Haven't done so in RPM heads, but I've put 7mm titanium valves in 452 iron heads as well as Stage 6 heads. I think I'm going to try the same with some of the chinesium victor knock off since they'll have the flow to turn the rpm to make the Ti valves really worth it. S/F....Ken M