I have used the Eldebrocks on cars, but not a boat. My experience was very good, they work and don't have much that goes wrong with them. The metering rods work very well.
What are you doing with your old Holleys?
79 28' Mariner twin inboard V-drive. SW Lake Erie: Maumee Bay & The Islands
I did not have much use for the old carbs. The mechanic has spent a good deal of time giving me free help and advice so I was happy to pass them along to him.
One of the carbs totally seized with the secondary cans open. As a result the engine would not drop down below 1500 rpm. The other was probably salvagable but it seemed like a good idea to replace them both.
The only glitch was the Eldebrocks are a slightly different shape making it necessary to relocate the coolant reservoir. Otherwise they slid into place very nicely.
I also notice that the throttle movement is more sensitive and takes a little getting use to.
It is always a tough choice to know whether to repair the old parts or replace with new. With the mechanics charging $70/hour and up I am inclined to go with replacement in most cases.