push rods are the same, no sense in changing them, the 5.7 springs you have will work, the 6.4 springs may be better, they use the same IH seat diameters and retainers so they drop right in. I did my swap without any tuning or the expensive 6.4 springs and its fine, a definte improvement with no other changes so if you can not change your tune you should still be in good shape. I used a MDS cam because I had already bought it for my 1/2 ton and its great, I doubt youd see 5 hp difference as the changes for MDS are super tiny, I have run MDS on a non MDS cam and it is fine that way also.