Mine had stamps like that and one pair had the holes in one end for a water crossover. According to the seller at Cilumbis Ford Expo 86 swap meet the heads were used on David Pearson's Torino with a box intake that had nbo crossover. I didn't get the intake but silly me in not asking about it's availability of ithe intake. Years later when i bought some pentroof valve covers with weird air fittings I never asked and missed the whole 68 Championship winning Nascar Torino that was run at Evergreen Speedway in the 70's.