460 based aluminum Alan Root block , SVO A460 heads , Crower crank and rods. A 4.600 bore and 4.75 stroke is possible but would be 632 CI. Yes 99% sure it is a Carroll Shelby Engine Co built engine by the CS006. The engine co. was bought by Bill Denbeste and moved from So Cal to Nor Cal , so "I" am not sure they still have the build information. The large extra accessory drive was standard on those blocks and could be configured as an oil pump but was most often used to locate the distributor ( magneto) when a Rootes supercharger was used. Aluminum main caps were an option back then. Ford sold the blocks and eventually Raceparts Distribution Inc ( gone now) took over block manufacturing , eventually selling the rights to Carroll Carter who still sells them today. Blue Thunder valve covers , custom made oil pan.
Randy