my holley had seen better days, this is after 750 hours without a rebuild:
it took about 20 mins to swap them out and a friend with a tube bender made a new fuel line in about a 1/2 hr. he tuned it in about 5 mins. definitely just a 6 pack type job.
i've taken it on the water once and it ran great. no hesitation, strong out of the hole, and most of all i can't wait to see how long a tank of gas will last now.