The engines were made by Rocketdyne, then part of Rockwell, more recently Aerojet Rocketdyne which per the internet is owned by L3Harris. Harris, of course, is best known for the development of offset printing presses and the Harris Intertype typesetting machine that competed with Linotype.
Upon further review, I was wrong.
I read now that Chrysler was credited with building the S-1B stage; not the engines themselves.
The mid-sixties were 60 years ago, guess I misremembered what I heard attending school in Brevard County. My father, brothers, and brother-in-law worked construction at the VAB and elsewhere on the Cape.