IH full-size axles are spring over, same width as chevy, and have more normal caster (5-6*) than a scout.
Depending on which D44 Closed Knuckle front you are considering, it could be just a strong as an open knuckle. The 8-lug should be a "big-ball", which has the larger u-joint.
If they're from the mid-to-late 60s, they're likely 4.88 gears. Rear may have a power-loc, but don't expect any true lockers.
They'll have drum brakes, which aren't terrible for on-road use. In fact, the power 4-wheel drums on my 1/2 ton IH pickup stop great. A disk brake swap is possible, but I don't have the details handy.
Some more fun facts - IH went open knuckle with drums in '72/73 and went to discs in '74. 74/75 rotors are nearly impossible to find new and are spendy if found used in good shape.
I'd be more concerned about the turning radius. CK front axles have a much worse turning radius than open.
I'd go with the suggestion above for the front axle.
The rear could be used easily, but you may have to shorten the drive-shaft depending on where you set the pinion angle and your ride height. This would be true of any beefier rear, due to the longer pinion.