Saw the predecessor to that, a 221 in a pick n pull. Would have grabbed it if nothing more than novelty and history. Quite rare indeed. The small 3.5" bore really limits head and valve choice.
Well there was the 260 SBF with a 3.8" bore. When they tested 1/4 mile times between the SBF Cobra and a 7 liter, the SBF was actually quicker. Revealed later was the fact that the SBF engine Cobra was actually a 260 with Shelby majic applied. The problem with the 427 street cars of the day was the bias ply tires and the 427 torque, 480 lb/ft and possibly more. That is what they admitted to. Kind of like the admitted to 425 HP. In a similar vein the 426 Hemi was factory rated at 425 HP, but on one of the Saturday morning HP shows they interviewed one of the Chrysler engineers. He stated they could take any engine off the assembly line to dyno and get 500HP gross. Now some engines would have all parts tolerances stack up just right like a blueprinted engine. Those would produce 25+ HP more.