moving rear end back

Can't tell you for sure, but I would think, if you did move the rear back you would have to drill the shock plate to match.

Reasoning behind the thought. Just did a rear swap from 7.5 to 8.25. Noticed the three holes in the perch and made sure that I got it in the middle one. On the spring plates I just had a centre hole to align. I would think that if the rear is positioned further back by using the front hole as it were on the perch, then the shock plate would be in the wrong spot to fit flush to the spring and allow the U bolts to bolt up. The shock plate having just the centre hole would not move back far enough.

If you drilled the plate a like distance then you could move it back a like amount and have the U bolts bolt correctly.

No info on this, but I'd wonder what moving the rear back like this (never done it myself) would do to brake hose movement. Would it be too tight to allow suspension travel without damaging the hose? Shock alignment. Would they have clearance operation issues? Drive shaft length? Long enough without weakening the connection at the trans? Spring operation now the pivot point is moved back and angle is different?

Above just things I'd be wondering about with the move. Not interested in doing the move myself, but always interested in learning new things.

Cheers