Those heads look better than most aftermarket heads, in that they DO NOT cut down the NUMBER of fins compared to stock, which many drag racing oriented heads do. BUT they are NOT "fat fin" in the way the Bob Hoover was working on. He was tig welding additional fin AREA, so the whole head would get grow, in planes parallel to the valve cover gasket sealing surface. See below, which is a NOTIONAL plan view. The magnenta is the added fin area.
View attachment 86918