Choking Gap by John Joseph McGraw
Luther Hayes, brutal boss of a gang of jayhawkers, is plenty sore at Daco Ward for giving the evidence that put him behind bars for thirty years. When he is sprung from jail he goes looking for Daco, to settle the score, but failing to find him, Daco's wife gets the bullet instead. Prepared to follow Hayes all the way to hell to get his revenge, Daco's trail is hard and long, but a partnership with big Tondu Adams lightens the load and the pair are soon on course to wreak havoc on Hayes and bring the brute to justice.