"Z06 LS6 243 heads, GM part #12564824. The good ones with light weight hollow intake valves, and sodium filled exhaust valves. These were removed from an August 2010 GM part #89017653 crate engine after approximately 1000 kilometres."
found these heads for sale i plan on doing a 6.0 swap in to my 85 shortbox one day and was wondering if these would be worth picking up?