Film critic Gene Siskel thought that Jack Nicholson’s second directing effort, the comedy-western Goin’ South, was just okay, giving the film two and a half stars out of four. There was at least one way it could have been better, he said. “The film could use more of John Belushi, the Animal House star, wasted here in a walk-on as a fat Mexican deputy sheriff.”

There was someone else who believed Belushi could use more screen time: John Belushi. And he would have had more scenes if he could have behaved properly. But things were goin’ south right after Belushi signed on to the project for five weeks of work at $5,000 a week. “What the hell does John Belushi want to do this for?” wondered Nicholson, according to Daniel De Visé’s The Blues Brothers.

Good question. Belushi was a mess when he arrived in Mexico for filming. Producers...