Just wondering what I should pay for a set of used iron (not aluminum) L98 heads should run me used.

Would these be ok for a budget built L98 using the ZZ4 cam?

 

First thing you should do is expect the worse...call a machineshop and ask what it would cost to do a complete rebuild on them...compare that cost and what you need to pay for them, against the many aftermarket heads that can be used out of the box.