Do these exist. I've seen chips but no programmers. And what would I gain being that my truck is a manual and I control shift points.

 

Any "chips" you see will not work. This is a PCM controlled system, flash programmers that change the PCM file do work. Look into the SCT xcal 3 from any of these fine custom tuners. They will all be able to tune the 4.2L:

http://www.troyerperformance.com/cgi-bin/ppistore.pl
http://www.vmptuning.com/store/index.php?
http://www.powerhungryperformance.com/

 

Im in the same boat. I have a 4.2 stick, the only one ive really seen is the one from Edge, i havnt looked into it too hard though.