Ok on the primary:
The 6.5 PV just means that's when the PV opens. You could try an 8.5 PV that will make it richer sooner.
But the number you also need is the PVCR, Power Valve Channel Restriction, the size of each of 2 holes drilled in the metering block behind the PV. THey show as .038" for your carb but I'd check for sure.
While in there, the secondary metering plate should have a number stamped on it like "34". From this you can look up the hole sizes near the bottom, these are like the secondary jets but they don't flow the same as jets, but you do need that hole size to get started.
Meanwhile here is another easy thing to try:
Clamp the vac secondary SHUT, and try it again ie as a 2bbl. Does the problem go away? Can you now jet it leaner?
Maybe the secondary is too lean or more likely opening too soon.
