As a European I have a soft spot for inline 6es in intermediate or compact Body styles, as this was what you would usually be able to afford at best to go high Performance over here and weight Distribution for our Kind of winding roads was superior as well.
I think Doug Dutra is still in the Business with parts to soup up These engines.
" Can be parted out for the selling price. Fenders, doors, trunk lid, hood, trunk floor, floor pans inner fenders, frame rails all solid and clean."
This part of the ad could be a bit alarming.
Another for me most desirable 6 cyl. option that Comes to mind was the not too popular Sprint Option from Pontiac for Tempest and Firebird around 1966-68 with the advanced SOHC and Timing belt setup.