George;

Maybe I'm missing something here too, but it sounds to me like a simple comparison of the dimensions of the old and replacement steering boxes and shafts should reveal the problem...if they are indeed the same length shaft, there is a limited amount of adjustment of the clamp possible on the splines (but Royo needs to obviously keep full overlap and clamping on the splines). As far as I am aware, there was only one size rubber coupling made (for the 1800), so there's no adjustment possible there. I also suggest snaking a pulling wire for the horn wire while the assembly is out of the vehicle...probably a lot easier than trying to do it while installed (too late maybe).

Cheers