You can use Tunercats/jet DST and the def. file for a 2001-2002 truck.
The 01-02 fullsize vans used the Vortec 305 and 350 as an engine.
The 96-97 fullsize trucks and the 98-99 trucks PCM's are different the 98-00 PCM's use a VATS while the 96-97 doesnt.
in 1999 the older black PCM was used in the classic style trucks as well as in the Tahoe Limited Classic body style with a Vortec 350 in the classic body style.
Here are some older truck PCM pn's that drive the 4.3-7.4L engines.
16244210 1996
16208546 1996
16229684 1997
16250279 1998
09355699 1998
16263494 1999
Here is an example of the 411 PCM being used in a 98-00 oldbody style truck with the Vortec 305/350 engines.
http://www.pacificp.com/forum/viewtopic.php?t=3240
There is more tuning support for the 411 PCM as well.
If you use thePCM pinouts from a 2001-2002 5.0 or 5.7L van for the 411 PCM you can run any 96-2000 305 or 350.
I am sure other can help you out more.
peace
Hog