I wish I had a couple of my old 70's/80's shortboards because I kind of remember those boards being thicker and definitely carrying more foam toward the rails than today's shortboards at similar lengths and widths. I had a late 70's 6.8 'Something Special' that was probably 3+" thick. I also has a 'CANYON' by Rusty from the early 80's that was also a 6.8 and pretty darn thick with a flat deck that carried almost all the way to the rail line. Similar boards these days seem to be thinner, less volume.
Am I hallucinating?