Time relation in Aman

[Galin]

Originally Posted by Legate of Amon Lanc

(...) so (like e.g. in the biblical case) it probably should not be taken literally as number, but as representative of something, something that should bring you to note "there's something special about that year in Aman, in fact, something VERY special" (because it isn't just "any" big number, but "this" kind of number).

I'm not sure I agree that any special meaning behind 144 means that it did not yet represent the equivalent of 144 Solar Years, or that it should not be taken literally as a number.

'Time in Aman was actual time, not merely a mode of perception. As, say, 100 years went by in Middle-earth as part of Arda, so 100 years passed in Aman, which was also a part of Arda. It was, however, the fact that the Elvish speed of 'growth' accorded with the unit of Valian time that made it possible for the Valar to bring the Eldar to dwell in Aman.'

JRRT, Aman

This is from the same essay (later 1950s) that speaks of the Valian Year being equal to 144 years.