Here we have a film from the earlier days of Apollo. More correctly, early 1964, after Mercury but before Gemini, we had this historic test of a Saturn 1 vehicle with the first live upper stage.
To put this in perspective, when this rocket system, SA-105, was launched and successfully orbited, the S-IV upper stage (the primary subject of the flight) and the ballast payload which was launched was the heaviest thing ever placed into orbit.
The S-IV stage was a liquid hydrogen fueled high-energy upper stage, flown as a testbed for technologies that would evolve into the S-IVB that the Saturn 1B and Saturn V would use. The S-IV used 6 RL-10 engines, the same kind used on the Centaur vehicle, to deliver 90,000 pounds of thrust, enough that in later flights the vehicle could launch moderately sized experimental payloads into orbit.
Again, the focus of this film is the S-IV, and it contains some short but detailed commentary on the testing of the stage, as well as its behavior in flight, including amazing film of the actual staging and ignition of the 6 engines.
The mission flew with no major issues – a nominal flight, which showed that the S-IV stage would function as intended, and it would fly for 5 more missions before being replaced by the more powerful but still related S-IVB – a stage designed for the task of putting a fully fueled Apollo CSM into orbit, or the complete Apollo spacecraft, CSM and LM, on a course to the Moon!
As always, enjoy this little trip back in time.
https://www.youtube.com/watch?v=461Wcw-lD4k