'Spring over' for FJ60?

I wouldnt do the shackle extension unless your springs are good as youll have too much roll and bumpsteer.
Better to fit new springs that have a 2 inch lift.I paid $660 for my dobinsons from TJM (FJ73),60 series are the same price.

The hilux started its life as a 2wd ute.Later on when Toyota needed a 4x4 in this class ,the cheapest way was to convert the existing body.The problem was, there wasnt enough room for suspension travel or clearance for bigger tyres under the old fenders. The springover fixed this.
The reason the landcruiser doesnt have a springover is because it was a purpose built 4x4 with all the right geometry designed into the body negating the need for the springover.

SOA have been done on plenty of 60s series. Fundamentally its the same as a 75 series.Do a search on IH8MUD.Its a mainly US site with pics and tech articles on suspension including 60s. Also Outer limits 4x4 forum ,an aussie site,have owners who have done the SOA and bodylifts.

Maquarie 4x4 in Windsor NSW have plenty of them running around Sydney with spring over conversion. Last time I enquired it was around $3000. They have to cut the swivel hubs off the axle ends, rotate the diff upwards and then re-weld the hubs back on to ensure correct caster angle for steering.