Carter TQ - VERY rich at WOT...how to troubleshoot?

JC71340 said
I'm no expert, but as others have stated, I thought at WOT there was normally almost NO vacuum, isn't that a primary indication of something completely un-related to the carb? No?

Typically 'no vacuum' can be 1/2" to 1.5" Hg, ignoring 2 bbl or restricted v-8 engine.
Running with vacuum secondaries and a somewhat slower opening spring my 340 will get to around 2"Hg. Same engine on dyno running WOT on primaries only the vac is close to 4"Hg at 5700 rpm.