I feel like it makes no sense that a hardline segregationist like Wallace would pardon a black man who had previously been accused of rape.
I'm not an expert in the subject, but I've just watched a couple of documentaries that touch on the life of George Wallace - Settin' the Woods on Fire and The Reconstruction of Asa Carter - so I thought I'd offer a couple of thoughts.
The first is merely a caveat: Wallace didn't personally pardon Clarence Norris in 1976; he merely signed an order that had been unanimously approved by the Alabama Pardon and Parole Board.
But more importantly, I think Wallace adopted racist rhetoric not out of conviction, but rather because it won him elections. When he was a judge in the 1950s, he stood out from his colleagues because of relative liberalism on matters of race. As one black lawyer, J.L. Chesnut, put it in the documentary listed above:
"Judge George Wallace was the most liberal judge that I had ever practiced law in front of. He was the first judge in Alabama to call me 'Mister' in a courtroom."
When Wallace ran for governor in 1958, he was endorsed by the NAACP, while his opponent, John Patterson, had the backing of the KKK. Wallace and others had the perception that he had lost the nomination race because he was considered too soft on the question of segregation. His aide Seymore Trammell famously recalled Wallace saying, "Seymore, you know why I lost that governor's race? ... I was outniggered by John Patterson. And I'll tell you here and now, I will never be outniggered again."
Or as he was reported to say: "You know, I tried to talk about good roads and good schools and all these things that have been part of my career, and nobody listened. And then I began talking about niggers, and they stomped the floor."
When he ran for governor again in 1962, he adopted a more hard-line segregationist, enlisting Asa Carter, a charismatic KKK leader, as a speechwriter and operative. It was Carter who penned his famous "segregation now, segregation tomorrow, segregation forever" inaugural speech in 1963, using a pastiche of phrases drawn from Klan newsletters. (Carter later remade himself as a novelist, writing the book on which The Outlaw Josey Wales was based, and presenting himself as a Cherokee mystic in The Education of Little Tree).
Wallace played the role of arch-segregationist with relish, so it's hard to know how much of this was an act and how much came from a genuine animus toward black people. Probably, like a lot of public figures, he got so used to playing the role that it became a reality for him.
That being said, in the late 1970s, Wallace became a born-again Christian, and his conversion experience led him to recant his previous segregationist positions, and to make amends with those he had harmed, including the African-American community - making a record number of black appointments to state positions in his last term in the 1980s.
So I'm not certain that the pardon of Norris was entirely out of step with the rest of Wallace's career. But if there is someone with more expertise in this area who has a different view, I'd love hear it.
(Aside from the documentaries, I'd also recommend Dan T. Carter's The Politics of Rage, which looks at how Wallace tapped into a right-leaning wave of national politics from the 1968 election onward.)