The magic word "around". I've seen quite a few 4V CC heads sold for around the $600 mark. For those kind of $ your are looking to reco them anyway. I've also seen them sell for upwards of the $600 mark but they require minimal or no work. I've also seen 2V heads sell for upwards of $600. Dearest set of 2V's I've seen sell was for just a tad over $2400. I sold the 2V's that I ran the 12.95 with a stuff auto for $600 bare. The new owner knows what they are capable of. My 2V's cost me $250 in absolutely buggered form. I spent $3700 to completely finish/accesorise them. My bad
You just have to be in the right place at the right time. A $600 set of 4V cc heads I personally wouldn't call a bargin. As the $ required to get them upto scratch is better spent on alloy heads. The uninformed have no idea alloy heads are available though. So $ can be dragged from their pockets. All depends on what class you drag race in. If you drag race? Some class's won't allow alloy.
I personally wouldn't be slightly interested in 4V's. I've seen the light with alloy heads and will never go back. I did research 4V's prior to my alloy head purchase though as I wasn't aware of any other head that would suit my needs.
The moral is :They are only worth what someone is willing to pay regardless of what they are.
The beauty is some owners of 4V engines don't know what they have got in their possesion. So things sell at bargain prices when your in the right place at the right time.