As part of the Space Launch System (SLS) program, NASA had been running the Advanced Booster Competition, which was scheduled to end with the selection of a winning booster configuration in 2015. In 2012, Pratt & Whitney Rocketdyne (PWR) proposed using a derivative of the F-1 engine in the competition as a liquid rocket booster ... The F-1B engine has a design goal to be at least as powerful as the un-flight-tested F-1A, while also being more cost effective.
Developed during the later stages of the Apollo program, the F-1A was test fired, but never flew. Several were crated and stored by Rocketdyne (later Pratt & Whitney Rocketdyne). The company has also maintained an F-1/F-1A knowledge retention program for its engineers for the entire period the engine has been mothballed.
And this engine lost the SLS competition to the SSME+solids. So yes, it's an interesting point that the Saturn V engine might still be buildable, but it's not cost effective today, and it's not the Saturn V rocket.
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https://en.wikipedia.org/wiki/Rocketdyne_F-1#F-1B_booster
https://en.wikipedia.org/wiki/Saturn_C-3#Pyrios
Also, https://arstechnica.com/science/2013/04/new-f-1b-rocket-engi... .
And this engine lost the SLS competition to the SSME+solids. So yes, it's an interesting point that the Saturn V engine might still be buildable, but it's not cost effective today, and it's not the Saturn V rocket.