Here is a photo dump from installing larger torsion bars on my 4x4 van.

Basically you have to compensate for the the bars being 2" longer.

Here is the donor car:
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Here is the stock 4 runner rear bracket. Welds ground down. The lathe was handy but not required. A grinder would be fine. You can see my note of 2.75" is the desired length on that side. Next step is to hammer the tube to the rear.
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Tapped and rewelded. 2 passes with TIG. Remember these components support the weight of the car.
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Now for the front:
Stock runner bracket, getting the ears chopped off.

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New front brackets using the 4runner spline socket.
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About 5 passes of welding. Root with TIG followed by stick.
I used 1/2" plate, Probably over kill. 3/8 would probably be fine. Maybe an engineer out there can do a strength conversion of 1/2 cast iron to plate conversion.

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spacers are needed on the front to clear the rear a arm bushing.

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On Each socket there is a large idexing tooth. Its really hard to see even when the spline socket are clean. They were not where i needed them to be and had to be ground down with a die grinder. Now there is infinite rotational adjustment options to setup your preload in the back.

Ride is much softer at the same ride height. Much less rebound response when hitting bumps. I think i am 18.5" hub to fender.