340 heads??

I have a set of 1970 340 "O" casting heads(2.02). The "white book" says the 1970 340's and 340 sixpacks used them. They've been hot tanked and magnufluxed and are totally rebuildable with no cracks. I also have a full set of brand new Ferrea stainless intake and exhaust valves for them. I'm just curious what these heads would be worth if I decided to sell them with the valves or even without. Anybody got a ballpark figure. I think they're pretty rare as most 340 stuff is nowadays.