I've done a couple, plus other IH's similar, but mine have narrow front ends. I prefer to block the front, but I have a chain hoist on a beam to hold the engine/front end in place and roll the rear end away. When going back together engage the pto, put an adjustable wrench on the pto shaft turning it to move the tractor back together. I do this by myself, so using the pto to move the tractor saves a lot of pushing, and maybe getting out of align. When it's close enough I use 8" long bolts threaded in basically guide pins. Once the input shaft is starting to mate with the splines on the clutch disc, you can feel them mesh through turning the pto shaft. From that point on I use shorter bolts, then roll forward by hand and chase it up tightening the bolts as I go. I also fill the dimple in the front of the input shaft with a good bearing grease to lube the pilot bushing.