Reverse tape help!!

Hmm, the GX4000 is a quarter track stereo that first records on track 1 and 2 (l+r), and when you swap the tape around, it will continue to record on track 3 and 4 (l+r). Therefore, on playback, it needs the playback head to only play the 1 and 2 tracks (because when you swap the tape, track 3 and 4 are lined up to be played on 1 and 2). So simply swaping the tapes won't give you the effect you want.

Or maybe I'm missing something here, my mind isn't ready for logic today

I still doubt it, because I think these recorders actually use tracks 1-4 and then tracks 2-3, and you have to set a switch to enable playback of the desired channels. So you actually do have a playback head that physically touches all 4 channels, unlike I stated in my first post, and the switch determines which tracks are played over the outputs. So if you'd record on tracks 1-4, swap the tape as if it where to record or playback tracks 2-3 but then set the switch to playback tracks 1-4, shouldn't you hear the recording reversed?
I think it could be possible, because that whole karaoke Sound-On-Sound and Sound-With-Sound function you often see on quarter tracks takes benefit of the 4 track concept...

I could try it on my old Philips quarter track, but my mind is not only unfit for logic, it also isn't ready for any exercise.

well i dont know this specific recorder. but the 1/3 and 2/4 arrangement is standard. the head would physically touch all tracks at the same time, but it only plays back the ones you are supposed to hear, otherwise you'd har reverse sound all the time..