How do i set timing on 1998 chevy truck 350 vortec

number 1 plug wire should be pointing towards the front drivers corner . drivers side piston order is 1-3-5-7 front to back .passengers side front to back is 2-4-6-8 then the firing order is 1-8-4-3-6-5-7-2 . if you pull the # 1 spark plug and put your finger in the hole /remover power wire while doing this at the dist.bump the engine when you feel a rush of air that's the compression stroke when the piston is at the top of it's compression stroke . pop the cap look to make sure the rotor is pointing at the # 1 piston roughly and place cap back on so the # 1 terminal is over the wire end of the rotor contact tip and work clockwise around with the firing order and hope this helps .if it still dont want to run then you may have jumped timing chain or stretched they will jump out of time and cause a headache.

Timing is not adjustable. There is a "Cam ******" that is, but a scanner is needed to adjust it. Its basically lining up the rotor to the dist cap.