Yes it can be done and has been done before,Iv'e seen a couple of them on ebay before and I know some one that is going to put a 7.3 powerstroke in their 96 bronco.The 87-91 250 and up were available with two different diesel engines, the 87 had the 6.9 International diesel and the later years had the 7.3 international diesel.The best thing to do is what the person I know is doing with theirs, is looking for a mechanically good F250HD-F450 cheap enough (maybe a rot bomb or accident vehicle) around the same years that way you have everything you need to do the swap and know where everything goes and if you get a 250 or 350 you can think about upgrading the axles and suspension to 3/4ton or 1ton.Iv'e seen people use the stock ford 8.8 rear axel with their swap but I wouldn't count on it lasting long especially if you like to romp on the gas.I believe awhile back Iv'e even seen an 87-91 bronco on here that someone put a diesel in.