it is a process , typically & raise both ends as high as possible put the stands at the front of the leaf spring where it cannot slide back & leave as much weight as possible on the rear so yes I usually have the rear tires on but not always , I have used an engine stand to lift the front once , it just got in the way so from then on I just lifted the car with my legs grabbing the front bumper or bumper brackets & had a friend raise the stands as I lifted roll the engine under the car usually through the wheelwell where there is the max clearance , then lower the nose right down , often I will lower the rear also until the frame sits on the K member & line up the front 2 bolts , jack the rear & start the 2 rear K bolts & then try to get 2 bolts into the trans crossmember & & then jack the car up again slide under & tighten everything up & install the Tbars , bolt up the spindles to the lower ball joints .
The snowmobile pads worked great , BUT I often had to tweak the lip holding the castor so welding a brace in the corners would help as occaisionally the caster would get stuck in a crack or divot in the cement & twist the lip where the castor is bolted on , there are different styles that may work better than the set I had , I have seen modified engines stand frames & even wood dollies used , a fully dressed big block & trans on the K frame with steering & lower control arms is probably close to 1000 or 1100 lbs . I install engine with everything possible on them , exhaust manifolds or headers , intake & carb/s pullies , belts fan all wiring as it is easier to just plug the harness into the firewall , lower control arms , castor struts , spindles I usually hang from the upper control arms installed first .