74 duster power to manual swap questions

I did the same thing, but I got my first box from the junk yard and it was too loose for the track. I also welded the couplers together to make it work. I have sense changed to the FLAMING RIVER Stearing Box FR1540 and Coupler FR1505M. I used the pitman arm from the junk yard it had a lower profile than the power pitman arm. I think the new coupler was about $150.00 but worth every penny. Yes the 72 box should fit into the 74, and if you weld the couplers you may need to reinforce the weld to make the Tech. Inspectors happy at the track. I dont kow how to post pics on this page but if you like I can e-mail a pic.