75 Series Front Springs into the 60 Front
Why? 75 Series front springs are longer than 60 series front springs and fit with little modification. The benefit of longer springs is increased suspension travel.
Landcruiser 75 front leaf springs are similar in size to the 60 front springs. From the centre pin to the military wrap wrap (fixed) end is identical. The length of the 75 springs is 40mm longer than the 60 springs on the shackle end.
The 75 springs to fit will need to be those that have a 50mm lift in them and you will need extended shackles. Extended shackles will allow for the extra 40mm spring length and will allow the suspension to flex.
The below spring specifications may may make this info a little clearer.
HOW TO MEASURE LEAF SPRINGS