806's with two different valves
 

Got a set of 806 heads. One came off of my car the other i bought used. the valves are different between the two heads. both heads have stock valves that i know of. They are noticeablly different. different cc's on the valves different weight. what gives.

Done a little reasearch and it looks like the head i bought has had some sodium filled exhaust valves used.