That may not be the factory procedure, but a Peugeot mechanic recommended
this method because the cables can stretch over time. Also, these are not
super critical adjustments, in fact you can make the kickdown cable tighter
if you wanted the engine to wind up more, but you would have to deal with
jerky shifts.
On my '84 XN6, with the throttle and kickdown cables adjusted using the
aforementioned method, the engine winds out to 6000 RPM on every shift if
I have the gas pedal on the floor (in kickdown position). If I back off of
the kickdown position, it revs to about 4300 RPM at every shift.
If you have never taken your XN6 to 4500 RPM, you are in for a surprise.
That engine is rather dull below 3200 RPM. The torque curve starts to
roll off at about 5000 RPM, so revving it higher is usually pointless.
If you put a free-flowing exhaust on an XN6, you'll notice a big
improvement in high-rpm performance, however.
Joe
(I just had to make a comment about free-flowing exhaust!)