Hard to support Indy but...the valves they used to use were BBB -- BBB will build to any spec you want and provided a great valve when I sold Indy--hard chrome on the stem and a hardened tip is about all you can ask for and all you need if you are not forced induction etc
That company was in Argentina and provided valves world wide to many OEM mfg's They are good valves
All that being said Todd at Marsh Perf sells Manley Severe Duty for Indys for reasonable price if you desire an upgrade in quality
I have always said--if you don't bang the valve into something a $2 will do just fine IMO
Cheaper valves tend to develop a little ridge at the lock groove once assembled or run this needs to be sanded or filed just a tad before disassembly and dragging it through a nice guide but honest I have done some wild wonderful engines with STOCK valves--there is little sense in spending big $$ on them in a normal build.
Now if you have a NOS, Blown, alky or whatever well...that is different
Guide not too tight, high quality seal properly installed, rocker geometry best you can get it are the keys..oh..and don't let the valve hit anything. Thing is IF it does it will bend--the old "dropped a valve " line is when that valve beats that piston until it just can't take it anymore and finally the head comes off--if it did not hit it is Very rare that a valve just fails as a bad part IMO
High dollar valves are made from tougher alloy, have good hard chrome on the stems but BBB ain't no junk maker
Problems with valves are usually not the valves fault from what I see in our shop.
Manley is hard to beat as an upgrade!