SM Head Install... forgetting anything?

The gaskets that were leaking are the style that come with gasket sets and are for cast iron manifolds only. Do not try to use those on any headers, as DentalDart already found out.
Also, the tiny roll pin or dowel pin in the steering coupler was for assembly purposes, to keep the coupler body from falling off the column before the column was installed in the vehicle at the assembly plant. If the shoes are sticking out of the coupler body like that, the steering shaft is working its way up the column, or somehow the large roll pin that keeps the coupler in place on the steering gear input shaft is missing and the coupler is sliding down onto the steering gear further. Either way, look into it before this comes apart and you lose steering.