My Duster 340 had a beat up Edelbrock Performer 750 and I decided to put a brand new Edelbrock AVS2 650 on it. After 2 drives and consulting my Mopar buddy we put the Performer 750 back on and it woke the engine back up. So don’t overlook carburetor selection/tuning. I know you have a Holley, but you have a performance built engine, is the Holley gone thru for performance on your engine or is it just bolted on out of the box tune? I’m sure could have gone thru and gotten the AVS2 up to the build spec of the Performer, but out of the box that AVS2 seemed like it cut the seat if the pants fun out of the car. It ran and drove fine, just acted like there was no real power to put you back in the seat. So do not overlook the carb tune, just cause it runs fine doesn’t mean it’s tuned to match the capability of the engine.