Opinions please !!! trimming valve guides from the inside

[NARF]

I have a 2 g head with about 1k worth of port and valve work alone. everything is freshly machined and ready to go together right now. the head was sandblasted and cleaned with glass media before any machine work was done. after cleaning and machining we found media between the valve guide and the cast of the aluminum heads itself( we were busy cleaning oil ports and overlooked it). there has been 2 weeks in attempting taking the media out 1 by 1. it's so tight in you cant even get a tool in the gap to pick the media out. I'm sure with my luck it will fall out while the engines running, no doubt. Rather than risking damage to the deck, and the facts new guides would require a new cut and lap because of concentric run out, we had the idea to machine the guide ends (that are inside of the runners) flush with the aluminum surface... milling the media as well. Any downside I'm not thinking of? The guides length is all that's changing, I've also upgraded to a stainless valve.

 

[Rausch]

This seems to work well. I know (well, we know) one particular cylinder head guy that has had no issue doing this. Seems to hold up on even the most serious of builds FWIW.