if you have '69 carbs then they will open slower than the '70-'71's. pretty sure '69's have a larger kill bleed and a smaller orifice in the center carb that the vacuum hose hooks too. carb list #"s with a -1 after them was supposed to take care of that issue.
This. And any vacuum leaks anywhere in the "system" that actuate the carbs will affect their opening too.
