2 deep holes in the manifold itself ??? theres one not as deep on the drivers side also , TUBE nuts go on them .

you need studs in all the holes in the heads , especially on those 3 holes , or really long bolts and fender washers but i doubt you'll get a good seal on the gasket surface .

also set the manifolds on a known flat surface and see how badly they are warped , getthem planed at a machine shop or you;ll be chasing an exhaust leak like another member did ...