32 commercial truck steering box

[my4dv8]

I picked up a fairly decent 32 big truck steering box . I knew it was from a big truck as it had the 4 spoke steering wheel and a much longer column drop. No problem I thought, just swap those out. It is a RHD box which is what we want. No pitman arm with it. Dang I have 8 or 9 pitman arms and an F1 arm . None are big enough to fit on the splines of the sector shaft. A miserable 0.0984 bigger at the small end of the splines. Does anyone have any knowledge on these steering boxes? Is the ratio different ? The mounting flange is different and i think the hole orientation is different, but thats ok as there are no holes in the frame on the RH side.