""I replaced the primary metering block with a "Quick Fuel" unit. The QF has tiny screw it "jets" in the metering block behind the power valve.""

There is a good chance that this block moves more fuel.

These are your PVCR's (Power Valve Channel Restrictors). You can swap these out to add/reduce fuel once the power valve is open. The Main Jets, Power Valve (2 door and 4 door: each door adds more fuel), PVCR's, and the Main Air Bleeds (or High Speed Air Bleeds) all work together. You change one of these and it affects the others and the main circuit. (Note: dont worry about tuning the PVCR's at this time.)

Boosters:
Straight, Downleg, Annular, and the higher end units have replaceable boosters. There may be more but these are the common boosters. I attached a picture showing downleg (bend downward into the carb) on the right and it appears to be an annular (holes around the inside of the barrel) on the left.

The A/F numbers are now 2 points higher after exhaust change. You should always recheck the tuning after changes to the engine. You might have had exhaust leaks prior causing the sensors to be reading wrong. 2 points is a big change.