Slant 6 Rebuild Machine Work San Diego,CA
To help us all, how did you determine the valves are sticking? Symptoms or did you remove the valve cover and push down on them and see the spring doesn't push them back? Not an expert, but seems the only things would make a valve stick is a bent stem or sticky gunk on the stem.
Hate to put you on the spot, but you are flaming the shop and we are hearing just one side of the story. Many customers get mad after "doesn't work" and jump to conclusions and faulting others.