318, mild 340ish cam, Holley 600 which was professionally rebuilt. Upon reinstall, motor starts OK, can't find any vacuum leaks. 5 minutes in, motor refuses to run unless I maintain a very high idle with lots of manual choke. I adjusted idle mixture and confirmed bowl levels with no improvement. My suspicion is too low a power valve, a new 6.5 is installed. I don't have a vac guage. Do you think I'm on the right track to suspect the PV value?