Sounds like the rings haven't yet seated? Did you degree the cam or just match the dots? IIRC, and it's been a LONG time, Holley's come with a 12.5 HG power valve and you're only pulling 10 HG? So the PV is open the entire time you're idling?

'68 Fury Convertible
'69 300 Convertible
'15 Durango 5.7 Hemi
'16 300 S Hemi