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So I can tell you my setup--I've got a Samsung VCR/DVD combo that does S-video and component out. I'm capturing lossless SD video through my Blackmagic Intensity Shuttle TB. The OP's sync sound issue sounds like a frame rate mismatch—make sure you're importing at 29.97 if you're doing NTSC—some systems shorthand that to 30, while others actually capture at 30 frames and the drop frames accumulate over time leading to the desync.

In terms of things that make your transfers the best they can be, all I can say is make sure each piece of equipment you've got is optimal. Get a good VCR with good tape heads and clean the heads. Garbage in, garbage out.
 
I am using the VidBox for Mac. I can only set the max record time to 3 hours. The problem is I have some tapes that are 6 hours (EP). Is there anyway to get the VidBox to record for 6 hours?
 
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