Intake Manifold Gasket ?

So Ben, remove the dowels and leave them out??

Yep, The dowl pins and holes are the weakest point in the cork end gaskets and same would apply to a rtv bead if around the pin. With the pins left out the rtv fills all the voids.
The cast iron intake is a heavy rascal to sit in place. I put 2 pieces of allthread rod in 2 bolt holes of the left head to guide the intake down into place.