As far as I know they are the same as when Harold made them. They are simply tubular exhaust. Not equal length, short tubes, and a turd to hook exhaust up to. Not much better than manifolds.
put harolds spitfires on a friends (@DJVCUDA) 66 cuda with a 360 in it.. they fit great, not a big deal running exhaust (forget what size he had) and they made a huge difference over the 73 style 340 manifolds he had on it. i was shocked to tell you the truth..
