a little help needed 340 TA heads

a guy came thru the shop a couple days ago with a worn out motor with t/a 340 heads on it, complete with rockers push rods etc. my problem is i dont know what is reasonable for both parties? i have never seen theese heads before let alone a chance to buy a set. the heads are on a worn out 360, witch i told him i didnt need, so he said make an offer on the heads. anybody know what theese heads go for?

thank you for your time and any help