8.75 Axle tube. HELP!!!!

I have a 68-70 B body 8 3/4 bolted into my 70 Duster with no mods to the springs or rearend, just to make it a roller. I put that part in bold for the nit pickers...lol. They are that close to being a perfect fit for a Duster, Demon, Dart Sport. Spring perches are cheap, so it doesn't cost a lot to buy a pair and move them in a half inch on each side. I know multiple people who just put a B body rear in a Duster by warping the springs out and bolting them down, but I'd never do it unless I was in a bind. You'll need the u bolts and shock plates to make the swap, plus shortening the driveshaft....then bolt it in and go! Rearend length list below.

https://www.forabodiesonly.com/mopar/threads/an-accurate-8-3-4-rear-axle-width-list.365494/