What are original 1971, 72 Z28 heads worth?

[bug garland]

I have a set of 336X dont have a clue what they are even has #43 on one intake port and #44 on the other can some say??

 

[Gary S]

The 3986336 heads do not appear to be a Chevy production head used on any cars or trucks. That being said, I suspect they are over the counter replacement heads that Chevy sold. If this is what they are, they were most likely available for lower performance applications with 1.94 valves, and also likely available with 2.02 valves for higher performance cars. The 2.02 versions will likely have screw in studs and guide plates.
The #43 and #44 on your heads likely indicate which mold they were cast in.