It's not the clocking that's the issue rather the space between the bottom of the steering box and the top of the pitman arm. The FSM says to measure that gap and replace the pitman arm to the same position along the pitman arm shaft. The gap in my car was 17.6mm. I don't know if I'll ever forget that number

Of course clocking between pitman and and shaft is important too. In my case the etched mark in the pitman arm shaft was centered in the gap in the pitman arm.

Next step? Buy a pitman arm shaft seal and replace it. That's about all the FSM says to do. Measure the gap between the steering box and pitman arm, remove the safey circlip below the pitman arm, remove the tangential clamping bolt holding the pitman arm to the pitman arm shaft, remove the pitman arm (I used a common pitman arm puller), remove the seal (pry it out with a sharp object being careful to not nick the pitman arm shaft), installation is the reverse of removal. Well, not quite. You'll want to clean the pitman arm shaft with very fine abrasive. I covered the splines with plastic wrap to protect the new seal on the way up. The FSM calls for sealant or thread locking compound on the splines, I forget which. Tap the pitman arm back to the specified gap.

Do you have a copy of the FSM?

Sixto
87 300D