what is the square eghuast looking thing below the two middle intake ports on the middle iron? is this just late 12'a?

 

ACV port. Air control and check valve. All 12As had this except for a few rare models with a stupid EGR port on the top. Block it with quicksteel or devcon if the engine is apart and you can clean the carbon out of the port. If it's assembled you will need to block the acv mount on the intaek manifold with a plate. They cost like five bucks and RB or MZTX.

If you ever have to pass emissions, don't block the ACV port. The air pump flows air through this port under certain conditions.

 

thank you

 

Like mine.

That stupid EGR valve is expensive, too.