trying to figure out information on my engine

[Vincent]

Need help loading pics i cant find out what the codes on the block mean looked on web hopeing someone can help bought a car with this motor just want to get it going but dont know anything about it all i figured out was that the aftermarket rockers were loose and one pushrod is bent

[Ringo64]

First off,

 

Information about what engine you have in your GTO will certainly help. If you need to post pictures, please see this topic about how to do that: https://foreverpontiac.com/topic/48-how-to-post-photos/