In article mn.dd837dd1945fba5c.127094@snitoo,
says...

Brian Thorn presented the following explanation :
On Sun, 27 Jan 2013 07:48:00 -0800 (PST), bob haller
wrote:


wouldnt it be something if nasa decided to go back and use the F1
engine on a future booster

You do understand that's the point of this test, right?

Not exactly. The point of the test is to investigate an F-2. Or at
least, that's my understanding.

http://arstechnica.com/science/2013/01/saturn-v-moon-rocket-engine-firing-again-after-40-years-sort-of/

More like an updated F-1A, but yes, NASA could call it anything they
want (like J-2X). The F-1A was quite a ways down its development path
before it was canceled.

Jeff
--
"the perennial claim that hypersonic airbreathing propulsion would
magically make space launch cheaper is nonsense -- LOX is much cheaper
than advanced airbreathing engines, and so are the tanks to put it in
and the extra thrust to carry it." - Henry Spencer