I need to know what the cyl head torque and rocker arm torque is for a 1998 6.5 L GM turbo diesel.

This is the best I've found that's free;

https://cardiagn.com/sst-service-specifications-b-2b-engine

https://www.fme-cat.com/CylinderHeadTorqueLookup.aspx

Check this manual

all heads are staged down, RTM? read the FSM book ?
my guess you lost it or dont want to pay read it,
no year stated the books are issue dby YEAR
and country!
and then indexed by ENGINE
strike three. you are out, sorry..... (your in good company)
1000s of post like this, and still no one guessing,
i wonder why.?
hark 14 engines.

2.3 L 4ZD1 I4
2.4 L C24SE I4 (GM, Aus)
2.4 L C24NE I4 (Euro)
2.6 L 4ZE1 I4
3.1 L LG6 V6 (GM)
3.2 L 6VD1/6VD1W V6
2.5 L 4JA1 diesel I4 (Cameo, TH)
2.8 L 4JB1-T turbo diesel I4
3.0 L 4JH1-T turbo diesel I4
3.1 L 4JG2 turbo diesel I4
2.2 L X22SE I4 (gasoline) gen2 begin...
2.2 L Z22XE I4 (gasoline)
2.2 L X22DTH I4 (diesel)
3.2 L 6VD1 V6 (gasoline)
3.5 L 6VE1W V6 (gasoline)

what country. ??????????????? why skip this???????????
what engine option (size and cyl count)
what state (California or not?)
are you replacing it, or just curious?

the 02s sensors in USA are 1 before the Cat and 1 behind.
but can vary by if car has 2 or 4 cats.
or if car has Y pipe.
not any one here can guess this.... ever.

unless, you answer above.
now the SHOCKER, WHAT ENGINE>?????

2.3 L 4ZD1 I4
2.4 L C24SE I4 (GM, Aus)
2.4 L C24NE I4 (Euro)
2.6 L 4ZE1 I4
3.1 L LG6 V6 (GM)
3.2 L 6VD1/6VD1W V6
2.5 L 4JA1 diesel I4 (Cameo, TH)
2.8 L 4JB1-T turbo diesel I4
3.0 L 4JH1-T turbo diesel I4
3.1 L 4JG2 turbo diesel I4

for sure.

The 12mm head bolts torque to 15 ftlbs.
the 10mm head bolts torque to 9 ftlbs.
crosshatch pattern for the sequence.

http://olybrake.com/pdf/fel_pro_torque_specs_guide.pdf

Check here

The torque settings for the cylinder head on a 2003 Ford Ranger 2.5 turbo diesel WLT engine are as follows:

• Main cap bolts: 70 Nm (52 ft-lbs)
• Head bolts: 65 Nm (48 ft-lbs)
• Rocker arm shaft nuts: 25 Nm (18 ft-lbs)

It is important to note that these torque values are for the cylinder head bolts and main cap bolts only. Other fasteners on the engine, such as the oil pan bolts, may have different torque requirements.
It is also important to use a torque wrench and follow the proper tightening sequence when installing the cylinder head. Consult the service manual for your vehicle or a repair manual for the specific tightening sequence and additional torque specifications.
I hope this information is helpful. If you have any further questions or need additional assistance, don't hesitate to ask.

You don't. They are non-adjustable hydraulic lifters. GM's spec for torque on the rocker arm nuts: Tighten the valve rocker arm ball studs to 47 N·m (35 lb ft). Once the valve rocker arm nuts are installed and properly torqued, no additional valve lash adjustment is required.

the rocker arm torque specs for the la1 gm 3400 sfi v6 is 168in lbs or 14ft lbs and 30degrees past that hope that helps you it came straight from my local dealer!

I presume that you are connecting your Intake manifold to the cylinder head after replacing your intake gasket, if so they are 30ft lbs, and 360 in pounds. Hope that helps