71 198 slant 3 on tree

I’d to

u look at their pic it can’t be used on slant 6 manifold as it’s a 2 bolt only hook up and this adapter has 4 . But photo could be not actual product
Just because it has four bolt holes on the one barrel side doesn't mean it won't work. If two of those slotted bolt holes will line up with the slant 6 bolt holes on the intake it will bolt on and work. My only worry would be how high they sit and whether the hood would close.