Exhaust manifold

yeah, no carriage bolts, but some of the later 318, I'm talking late 80s, manifolds weren't tapped for threads. They had a bolt/nut combo where the nut was a clip nut that simply clipped onto the manifold's flange
IC, this is a 74... I need more info
I was going to thread the manifold bolt holes...
strange someone would use carriage bolts... really strange