I noticed that my new speedometer cable comes straight out of the Muncie case and rides firmly on top of the shifter linkage. Since the shifter, linkage, and bushings are new, and the bolts are nice and tight, then I'm thinking that the cable could be the reason why the shifter locks up sometimes.

Do I perhaps have the wrong speedometer cable? I'm wondering if it's a Chevy speedometer cable which connects to the passenger side of the case where there's no linkage to worry about. Or do they all come straight out of the case?