When I was looking for an engine to see if it would be cheaper to buy or rebuild mine, I found a low mile ALH for $2k. I don't know that I'd pay $1500 for a broken one with unknown problems. Valves for the AHU were somewhere around $18. To get my whole head rebuilt with all new parts, not knowing my AAZ parts would work, I was quoted $450, but that was all valves guides lifters, springs, retainers, everything except the cam. If the piston(s) are damaged, add hundreds more.