engine timing is on the ECM (acutally called Fuel Sync) ya need a scanner and unless you changed the cam its set at ~+1/0. this is done my moving the distributor a tad. your crank sensor send the signal via a reluctor to the ECM for this. you can tweak the crank senosr position a bit to change it tho not reccomended as it might freak out the ECM and put ya in limp mode.
The reason why he said no and must use a starscan what he is trying to say is the PCM is always correcting the timing .... straight from the manual ....CAUTION: Base ignition timing is not adjustable on
any engine. (refering to the 5.9L) Distributors do not have built in centrifugal
or vacuum assisted advance. Base ignition
timing and timing advance are controlled by the
Powertrain Control Module (PCM). Because a conventional
timing light can not be used to adjust distributor
position after installation, note position of
distributor before removal.
go download a the service manual off of Hemitruckclub.com for an 03 .. it has the 5.9L in the manual which will give you alot of info for your engine. ... you will see the manuals on the left side and do save target as instead of trying to open because it is a very large file in PDF .. Enjoy