Does anyone know the specs of this casting. It also has Revision D on them. These are oem aluminum Mercury heads off a later model (2014) MerCruiser 8.2L Mag HO engine.
I've seen a similar casting on the aluminum mercury 520/525 heads. I cant seem to find anything on these heads. I know they are not Mercury racing heads. Prior to any work, I am trying to figure out what I have.

The 8.2 uses the standard exhaust bolt pattern where the 525 uses its own pattern

I’m running the stand bbc pattern CMI’s.
I’m trying to find some specs on these stock aluminum mercury heads.
what sizes valves, what size chambers, how they flow.
looking to have them worked or replaced but I can’t find specs where they are stock. Any insight is highly appreciated.