How to sync the dubbed audio to original video?
I've had the same problem where the video and audio were compressed separately and came out with as two different lengths.  Even just a half second difference will mean that the audio at the end of the video will be out of sync a half second.

I don't know what editor you are using, but I'm using Sony Vegas.  So I'll give you the steps for it then just adjust for your editor.


First un-group the audio and video files if they are grouped by pressing U.
Synch up the first sound or word in the video with the audio.  It will be out of sych at the end, but that's okay for now.
Convert the length of the video into seconds and the actual length of the audio into seconds.  For your example you said it was a 90 minute video (5400 seconds) and an 88 minute (5280 second) audio.
Now divide the larger file by the smaller file.  5400/5280 = 1.022727
Now you know that the audio has somehow become 2.2727% shorter somehow.
Now you can right click on the video in your timeline and set the playback rate to .977  - This will shrink your video down to match your audio.