Clarke in his commentary recognizes the problems you raised:
"Here are six lines, or three distichs, the order of which seems to
have been disturbed by a transposition, occasioned by three of the
lines beginning with the same word verosh, "and the head," which three
lines ought not to have been separated by any other line intervening;
but a copyist, having written the first of them, and casting his eye
on the third, might easily proceed to write after the first line
beginning with verosh, that which ought to have followed the third
line beginning with verosh. Then finding his mistake, to preserve the
beauty of his copy, added at the end the distich which should have
been in the middle; making that the second distich, which ought to
have been the third. For the order as it now stands is preposterous:
the destruction of Ephraim is denounced, and then their grandeur is
set forth; whereas naturally the representation of the grandeur of
Ephraim should precede that of their destruction. And the destruction
of Ephraim has no coherence with the grandeur of Syria, simply as
such, which it now follows: but it naturally and properly follows the
grandeur of Ephraim, joined to that of Syria their ally.
"The arrangement then of the whole sentence seems originally to have
Though the head of Syria be Damascus,
And the head of Damascus Retsin
And the head of Ephraim be Samaria;
And the head of Samaria Remaliah's son:
Yet within threescore and five years
Ephraim shall be broken that he be no more a people."
Threescore and five years] It was sixty-five years from the beginning
of the reign of Ahaz, when this prophecy was delivered, to the total
depopulation of the kingdom of Israel by Esarhaddon, who carried away
the remains of the ten tribes which had been left by Tiglath-pileser,
and Shalmaneser, and who planted the country with new inhabitants.
That the country was not wholly stripped of its inhabitants by
Shalmaneser appears from many passages of the history of Josiah, where
Israelites are mentioned as still remaining there, 2Ch 34:6, 7, 33;
35:18; 2Ki 23:19, 20. This seems to be the best explanation of the
chronological difficulty in this place, which has much embarrassed the
commentators: see Usserii Annal. V. T. ad an. 3327, and Sir I.
Newton, Chronol. p. 283.
Matthew Henry deals with the sixty five years as follows:
Interpreters are much at a loss how to compute the sixty-five years
within which Ephraim shall cease to be a people; for the captivity of
the ten tribes was but eleven years after this: and some make it a
mistake of the transcriber, and think it should be read within six and
five years, just eleven. But it is hard to allow that. Others make it
to be sixty-five years from the time that the prophet Amos first
foretold the ruin of the kingdom of the ten tribes; and some late
interpreters make it to look as far forward as the last desolation of
that country by Esarhaddon, which was about sixty-five years after
this; then Ephraim was so broken that it was no more a people.
The Jerusalem Bible (1966 ed) attempted to repair the apparent corruption of the verses as follows:
8a The capital of Aram is Damascus,
the head of Damascus, Razon;
9a the capital of Ephraim is Samaria,
the head of Samaria, the son of Remaliah.
8b Six or five years
and a shattered Ephraim shall no longer be a people.
9b But if you do not stand by me,
you will not stand at all."'
They added a footnote to the "Six or five years more" saying:
'six or five' corr.; 'sixty-five' Hebr. Samaria fell in 722.
The translators apparently considered these corrections too speculative because the later edition (New Jerusalem Bible) now has the more literal rendering:
8 for the head of Aram is Damascus, and the head of Damascus is Razon;
another sixty-five years, and Ephraim will cease to be a people. 9 The
head of Ephraim is Samaria, and the head of Samaria is the son of
Remaliah. If you will not take your stand on me you will not stand
The New American Bible (1970 ed) rearranges the verses like the 1966 JB, but without any indication in the verse numbering that it's doing so. It starts verse 9 on the "But within sixty years and five". It translates the sixty five years as "within sixty years and five" with the footnote "Within sixty years and five: if the text is correct its reference is unknown."
The revised NAB at the USCCB website retains the rearrangement of verses but moves the start of verse 9 up to "The head of Ephraim is Samaria". The wording is now more literal. The verses are now footnoted as follows:
- [7:8–9] God had chosen and made a commitment to David’s dynasty and his
capital city Jerusalem, not to Rezin and his capital Damascus, nor
to the son of Remaliah and his capital Samaria (2 Sm 7:12–16; Ps 2:6;
78:68–72; 132:11–18). Within sixty-five years…nation: this text occurs
at the end of v. 8 in the Hebrew. Ahaz would not have been reassured
by so distant a promise; the phrase is probably a later addition.
Sorry I can't give a better answer, but your question is now almost two years old and has no answer other than mine, so I don't think a better answer is going to be forthcoming.