hi can I know if anyone knows the extra thread hole size thread pitch near the b series valve cover b16a engine cylinder head.
near the intake manifold near intake cam gear back side driver side ? on the cylinder head side...back side.. there is a threaded hole that is free there. on the back..threaded hole what size that?

there is a extra hole with thread in it don't know the size? does anyone know the thread pitch size?
thank you.

attatched that photo the big thread near camshaft cam gear intake manifold top left side back..?? rear..

 

3/8" NPT (pipe).