"F1 was a dog, engineering-wise, very low efficiency and rather crude. The better rocket engine of the time was the Soviet RD-170 which was more efficient, produced more thrust and could be throttled and gimballed in flight"
Referring to my copy of the Saturn V Haynes manual:
The "big engine" development programme which lead to the F1 began in 1955. NASA issued the contract for the actual F1 engine in 1959, with first delivery to NASA in 1963 and first flight in 1967. Also, four out of the five F1s fitted to each Saturn V first stage were gimballed for steering the rocket.
<http://www.russianspaceweb.com/rd170.html> says that the RD-170 development programme began in 1976 with first flight in 1985. That makes it roughly twenty years younger.
Is it really sensible to consider these two engines as contemporaries?
The RD-170 didn't fly until 1985, so could perhaps be better compared to the RS-25 Space Shuttle Main Engine (first flight 1981) which was also a highly sophisticated and reliable bit of kit - and with a better specific impulse than the RD-170 and derivatives. The RS-25 could be throttled and gimballed too. Here are the efficiency figures:
F1 Isp (vac.): 2.98 km/s (304 s)
RD-170 Isp (vac.): 3.30 km/s (337 s)
RS-25 Isp (vac.): 4.44 km/s (452 s)
Putting the RS-25 on the list is something of an unfair comparison because while the RD-170 develops a superb specific impulse for a kerosene fuelled engine, the RS-25 has the huge efficiency advantage of using hydrogen as fuel.
But the F1 wasn't bad for a gas generator cycle RP1/LOX engine: it's only about 10% down on the much later and more sophisticated RD-170 - which ought to have the higher Isp due to using a staged combustion cycle.
All things considered, I think it's a bit unfair to call the F1 engine a "dog" and rather crude.
Yes, it wasn't hugely efficient but that's mostly due to the RP1/oxygen propellant mix as much as anything else. And they used that mix in part to keep the size of the main fuel tanks down: trying to build a hydrogen fuel tank system which could hold enough to do the job of an Apollo launch rocket first stage would probably have been beyond what was feasible at the time. It's the same thinking behind using the same fuel for the RD-170.
What the Saturn V first stage had to do was impart a huge amount of impulse to the upper stages, and that meant enormously powerful engines and enormous amounts of energy in the fuel tanks.
So the relatively low efficiency compared to a hydrogen fuelled engine was the result of a sensible engineering compromise: accept lower efficiency and get a smaller rocket stage overall which didn't have to deal with the problems of just how make the stage big enough to carry enough low-density liquid hydrogen to provide the required total impulse, then keep the stuff liquid for long enough, and then pump it - engineering issues which caused big problems on the Saturn V upper stages. Both the F1 and the hydrogen fulled upper stage engines used their rocket fuel as a turbo-pump lubricant and guess what? It was easier to get that to work using RP1 as the lubricant/propellent than it was with liquid hydrogen.
The early F1s blew up in testing. The early hydrogen fuelled engines melted their injector plates. They all had design problems which needed solving. Trying to get a hydrogen fuelled engine of the power of the F1 working on time and in budget would have been exceptionally hard: you'd've been up against all the problems the F1 design encountered plus the additional problems of liquid hydrogen.
I suspect that if you were to look carefully at the design details, you'd find that the F1 engine was probably the most sophisticated operational RP1/liquid oxygen rocket engine of its era. It had to be sophisticated, or it wouldn't have provided the required performance while working reliably. If you want to find out more, try getting a copy of the Haynes manual for the Saturn V rocket: the things really are quite remarkable.
That book's got a lot of detail. For example: the F1's main thrust chamber was made from tubes: 89 pipes took 70% of the RP1 propellant downwards, 89 brought it upwards: for thrust chamber cooling. Part-way down the nozzle, the pipes were bifurcated so there were 178 down tubes and 178 up tubes. This whole assembly was brazed together as a single unit in a single operation in a large retort. Is that crude, or is it well developed and appropriate engineering?
Yes, of course more modern rocket engines like the RD-170 and descendants are better but that's kind of the point of engineering: things get better in the future as more things are learnt, better materials are developed, design techniques are improved, and so on.