If you're running a 2.5 PV, that will have to be replaced and WILL cause a stumble on throttle stab. The original PV for that carb is 6.5. With a cam like yours, I'd run an 8.5. What that means is that the Main Circuit will be enriched via the PVCR's (power valve channel restrictors) when vacuum drops below 8.5" of vacuum. There is A LOT of misunderstanding around power valves..including the power valve video on Holley's website.
What's important about what's stated above is that the power valve enriches the Main Circuit. The main circuit does not come into play until the engine is between 2000 and 2500 RPM (closer to 2500). Until the mains come on, the engine is running through the Idle, aka, Low Speed circuit. The IFR's (idle feed restrictors) are what meter the fuel on this circuit. Another way to say this is that the power valve can be wide open at idle and it won't change a thing because the main circuit is not active....a lot of folks have trouble grasping this concept due, in part, to the misinformation out there. I have a classic example of a PV opening and closing that shows how the PV changes Air Fuel Ratio (AFR).
Here's my suggestion for this carb. Take it back to the config from Holley and start over. It's going to run a little rich on the low speed circuit, but it should eliminate or drastically reduce the stumble. The main circuit will be pretty close to where you want it for wide open throttle AFR.
Make sure the secondary throttle stop is at the original position as Holley set it up. That means to back off the throttle stop screw until there is an air gap, then tighten it until it touches and go an additional 1/4 turn, no more. Holley uses this same throttle plate on carbs up to 750cfm so the transfer slot behaves a little differently. Have the throttle plates been drilled? If yes, measure the holes and let me know the size and which plates are drilled.
Pri Main: 67
Pri PV: 6.5 (I think an 8.5 will work better for you)
PVCR: .039 (check with gauge pin if available or get close using drill bit)
IFR: .035 (also check)
Pri HSAB: .030
Pri IAB: .080
Pri & Sec accel nozzle: .028
Pri & Sec pump cam: Pink
Sec Main: 73
No Sec PV in this carb
No PVCR
Sec IFR: .039
Sec HSAB: .031
Sec IAB: .054
Edit: What is your altitude? The higher the altitude, the richer the original config is going to run.