Here is a "194" head discussion that was done a while back.
https://www.inliners.org/ubbthreads/ubbthreads.php?ubb=showflat&Number=54365&page=1I personally think the 184 valve is the proper size to use in a 194 head. The chamber could still use a bit of opening up. I have also seen a # of 194 heads hit water when trying to go to a 1.94 valve.