Z heads??? Help

[emnestor]

I have a 340 that I found and it has these largely marked Z heads on it. Im thinking they must be something from a 360 and also people have suggested that they are police car heads. Anyone know what these are???
Thanks

 

[OneBadDart]

look here... http://www.forabodiesonly.com/mopar/showthread.php?t=104943