Info / intake manifold

Hello group ,
Well I am looking for some info on getting the spiral type rivets
that I need to reattach my heat shield on the Aluminium .intake on my
1970 Chevelle SS 396 . They seemed to have gotten lost on the rebuild
and getting ready to finish up the motor for firing and need to attach
that heat shield back on .It is the original intake .I have seen them
but now can not find them so any help as to where a guy can look would
be appreciated .

Thank you ,
Bernie