Just want to throw this in before it is too late.
You mentioned Oring seals. Those are not much of a seal for a newly rebuilt head or your well worn head. It will pass just as much oil as before.
Your problem is worn guides. These umbrella seals will do a much better job of controlling oil.
http://www.ebay.com/itm/Viton-Umbrella-Valve-Stem-Seals-GM-Chevy-4-6-Cyl-Engines-11-32-Valves-/221346988752?hash=item33894f02d0:g:vgoAAMXQyFFTkizI&vxp=mtr
Another tip from Tom.
When trying to get the spring locks and retainers loose. Have a dead blow hammer or a block of wood to tap on the edge of the retainer to Knock it loose. They will come apart much easier.
Ordered the umbrella seals. Can you clarify how they install? I assume I just put them over the valve stem gusset. Do I need to put the O-ring back on the valve stem them or just leave them off? Removing them and re-installing them will likely kill them so I'd need new if I need to replace.
