Getting to the steering box once the engine is removed is easy. Don't forget that my Niva is RH drive. The first thing I did once I had the steering box removed was make up a very simple jig using some offcuts of timber. The purpose of this jig was to be able to locate all the holes in the pitman arm and steering box mounting holes relative to each other. I could then place the Toyota box on the jig and see how far out everything was. In order to be able to fit the Niva pitman arm on the Toyota box for this procedure I had to file the splines out of the pitman arm so it could slide over the Toyota shaft. By sliding the pitman arm as far up the shaft as the original Toyota arm had been I determined that it would end up being just under 10mm to low. This being due to the fact that the Toyota box extends that much lower below its mounting holes. For now I have called that "close enough". What sort of effect this will have on the steering or wheel alignment I am not sure about at this stage. If there are any negative side effects due to the centre steering rod being on a slight angle I will probably correct the problem by dropping the idler arm a corresponding amount. Lifting the steering box is not possible as the bolts pass through tubes in the chassis to stop the chassis from being squased. Bending the pitman arm is not allowed for certification reasons. The next problem to solve was getting the right splines into the Niva pitman arm. My idea was to use the splines out of the Toyota pitman arm by machining and turning the arm until we were left with a bush with the splines in the middle. The Niva arm could then be bored out to accept this bush and the two welded together. However the engineer I went to see to get this done felt that there wasn't enough metal in the Niva arm to do this safely. His idea was to build up the inside of the hole by metal spraying and then spark eroding the right splines back into the Niva pitman arm. This is being done at the moment. I will post a picture of what it looks like as soon as I get it back.
The next area to concentrate on was to actually get the steering box to fit into the car. As I mentioned before the brake booster gets in the way of things so that was the first thing to be removed. On the first trial fit it became obvious that the hole were the Niva steering shaft originally passed through the firewall was no where near big enough to accomodate the Toyota box as part of the casting ends up being inside the passenger compartment. Here are two pictures, the first one is a side view of the steering box temporarily fitted to the car while the second picture shows how tight everthing fits once the engine and startermotor are in place.