@DavidF: thanks, I'll check that, the pressure relief.

@lefty1: thanks for the input, I got the gearbox including pitman arm already.

@46gmcpu: I guess I should have said 3-groove pulley. Right now it's a 2 groove, however the front most is very narrow and I wonder wether it would even qualify as a pulley. In that sense I would need to replace the pulley anyway if I was to attach the PS to the crank.
Your other remark exactly points to my uncertainty: I've seen pictures on the net of many different setups which run of the crank pulley and/or the waterpump pulley, but nowhere why it would be alright to just change the setup form "regular".

regards,
Peter