this should be possible using the slip tool.
select the entire timeline,,
summon the slip tool (s), or simply grab it from the tool bar,
and type in + or -7.
(that’s 7, then a period, which FCP will read as 7.00)
it SHOULD work, but may not if the far end of the clips don’t have 7 seconds lea-way.
if you can find any problem clips, and trim them down, then you should be able to slip everything, then trim those clips back out.
be warned, though,
that any KEYFRAMING you have on the clips (volume graphing, motion fx, or keyframed filters) will also slip.
if you have any clips that you think would be affected like this,
then you can DUPLICATE your entire timeline up onto a higher set of tracks.
(Select all, hold OPTION + SHIFT and drag upwards)
this way you can slip only one set of tracks,
then copy paste the relevant attributes back
a better way to have approached this would have been to alter the TC of your original media to match the TC of the texted tape.
for safety you would transfer the original TC into the AUX tc field.
than copy the sequence into a new project, and capture, WITHOUT deleting the original media.
it’s a good idea to keep that as a reference guide
==================================
here’s an alternate approach:
make your sequence offline
(select all, shift D, use the “keep on disk option” of course.)
import the captured files into the project, open them in the viewer and change their TC to match the OLD TC.
now reconnect the sequence.
it should match the original sequence.
hopefully you have an exported version of the first sequence you can use as a guide.
once it’s all connected and checked, and verified as ok,
you can safely change the clips’ TC back to match their genuine TC.
good luck with it all,
nick