340 Help. Am I looking in the right spot to fix the issue

Was the cam degreed at the time of installation? If not then who knows where it is. You need to know where it lands with your timing set and keyway locations in order to move it to where you want it to be.

Also, Dyno's are not the be all, end all of how an engine performs overall, most don't start to record until 3k. The operator and/or maintenance (or lack there of) can throw numbers off. What gear was the the run done in?

Any track times?