If I rework a set of old castings to be what I would consider as equivalent as possible to new aftermarket heads(all new parts, over sized valves, improved flow, unleaded gas compatible, springs suitable for an aftermarket performance cam, etc)....... the cost is considerably higher than a set of Stealths.
The stock heads are more expensive even after you give the Stealths a look over.
But, how that shakes out is dependent on what machine shop costs are where you live.
Whereas the Stealths cost the same for the whole country........$1000.