cam degreeing kit?
You can take the gas pedal out and heat it up and bend it. Its not easy, you need a vise and a long rod to slip over the rod.
Holleys are worst, they take longer to open.
I think your cam is timed ok. By degree it you might find 1 or 2 tenths not no 2 seconds and 8 mph.
I think its in the carb. Check if the secondarys are free, if you over tighten the carb, I hear the throttle can bind up and not open. Maybe that carb needs the throttle 100% open. I like holley DP carbs.
I think you go faster with a holley BTW