Short answers, pulled from the story.
The Rocketdyne H-1 powered the first stages of the Saturn I and Saturn IB rockets, burning liquid oxygen and RP-1. Eight H-1 engines were clustered in each stage, providing the combined thrust to lift these rockets off the launch pad during the Apollo program era.
Starting the H-1 required applying a 500-volt AC signal to the Solid Propellant Gas Generator, a compact solid-fuel rocket mounted on the engine. The SPGG produced hot gas that built pressure to between 600 and 700 pounds per square inch, at which point a bursting diaphragm released that gas into the turbine to spin the propellant pumps. Because the SPGG had to be replaced after each use, the H-1 could be started only once per flight.
Surplus H-1 engines were reworked and renamed the RS-27 after Apollo, first flying on the Delta 2000 series in 1974. A later variant, the RS-27A, powered later versions of the Delta II until 2018 and also flew on the Delta III.
The Rocketdyne H-1 burned liquid oxygen as the oxidizer and RP-1 as the fuel. RP-1 is a refined kerosene first formally specified in Military Specification MIL-R-25576 in 1954. The mixture ratio was set at 2.23 parts oxidizer to 1 part fuel, within a tolerance of plus or minus two percent.
Early H-1 engines, used through Saturn mission SA-205, produced 200,000 pounds of thrust at sea level. From SA-206 onward, a revised production standard raised the rating to 205,000 pounds. Nominal combustion chamber pressure was 633 pounds per square inch, with the oxidizer pump delivering liquid oxygen at 3,330 US gallons per minute.
The H-1 descended from a line of engines North American Aviation developed after receiving captured German V-2 rockets at the end of World War II. NAA engineers solved a German 'waterfall' injector design that German engineers had never gotten to work, eventually producing the S-3D engine for the Thor and Jupiter programs before the experimental X-1 design became the foundation for the H-1. The key fuel, RP-1, was developed under Rocketdyne's REAP program starting in January 1953.