Roguefab hit a good point.
My 80 has the oil pan notched to clear the front axle pinion. You will want a bit more height/clearance, though mine can pretty much drop down low enough (with the airbags) that the wheels will touch the arches with 37's. So you will need some extra height, portals will add about 6" or so, and you'd need about a minimum of 2-3" of lift for the axle to clear the bottom end. Although, My motor probably could have gone a little tighter to the hood, changing the intake routing or the shape of the hood could give you some clearance.
Another thing, I would like to upgrade the front axle at some point. If you get rid of the high pinion front for a low pinion (dana 60 or something) and move the axle forward an inch or two you may gain a bit of clearance as well.