3/8"unc 1.6250" long stud for engine block to accept the
TAM2097 screw on filter head and for
HS2 carbs, alternative to this is
CHS2614 1.75" long and just over one thread longer.
LYG10008 bolt was later alternative for the filter head
UNC course thread for manifold or block and UNF for the nuts. See also
22A152 longer stud for some HIF carbs.