Got the Boost Valve Adjustment tool from Lingenfelter. A lot of discussion on setting this going on in the ZL1 section and of course the Caddy forums.
First, the service manual directions:
Reference 1:
Reference 2:
Reference 3:
The site here has them 'sideways' so you may need to download them to read them...
Now pics in action:
Tool:
Setup:
Adjusted:
Set the 'set screw' per service manual steps and good to go!
You can see I had to adjust both the valve and the set screw...
-Don