Ok well there are 2 ways to tackle this:

1) find someone who has the needed skills to do a custom chip for you - this may take several iterations to get it right.

2) go aftermarket ECM so you can tune it yourself.

http://www.diyautotune.com/catalog/megas...-unit-p-65.html + http://www.diyautotune.com/catalog/megasquirtii-to-gm-tbi-746747-adapter-pcb-p-187.html

51 GMC 4.2 turbo
Can't solved today's problems using the same technology/thinking that created them