yes, it is the 500 cu in Hemi Butch Leal raced in his 1982 Horizon (pictured below / restored by Steve Atwell, Sr.). Butch named his engines, the one I have which currently in his Direct Connection Hemi Duster is called "Big Red". With around 16.2 to 1 compression it has a bark unlike most Hemis.
Once acquired I flew Butch to Detroit where he verified authenticity....then we spent 3 days freshening it up. I manned the gunk tank and paid attention.
engine pictured below of how I acquired it, you can see the bulge (#1 cylinder) in the drivers side valve cover. I bought the Hemi before Butch arrived and we (Butch, Steve Atwell and myself ) discovered it was his "Big Red". Gil Kirks (owner of the Rod Shop) son was bracket racing the Horizon with a more docile Hemi after Butch left the Rod Shop. Bob Riffle (Butch's former crew chief for the Horizon @ Rod Shop) told Butch there were some "good" engines with the package Steve got when he bought the race car. He was right.