> I watch it as it captures and the audio sync seems to be fine
That's not useful. That only means the audio on the tape is in sync, because at that point you're not listening to the captured clip, you're listening to the playback from the tape. But that's a relief, means the problem is not with the master footage.
> but after it's done capturing I place the long clip on the time line and it starts out ok but after 10 or so minutes it is starting to not be in sync.
Play the clip in QuickTime Player and see if it's in sync. If the sync drift is still there, that almost certainly means the captured clip is also drifting. You can try using QuickTime Player Pro to chop up the clip into smaller chunks and then saving them as self-contained QuickTime movies, but it's rare that this would solve the issue.
Capturing hour-long clips from DV via FireWire was always a luxury, never the most reliable of approaches. If the problem is in the clip, you need to relog the tape into smaller sections and then capture. You can always recombine them afterwards if you need. Also, you're running the pipeline through a drive -- never conducive towards capturing good clips. You should consider capturing to the internal hard drive of the laptop first.
Check your current clip at five-minute, 10-minute and 20-minute intervals. Approximate where does the drift start to become noticeable? Once you find that mark, say 15 minutes, do a test by logging the tape at half the distance (seven minutes). Capture onto the internal hard drive in seven-minute segments and then check the resulting clips.
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