Getting back to your problem make an attempt to get idle down with things to check above. A 700 hp 588 isn't that Wild of a build. I realize big difference on CI however endeavour32's 509 650 hp's idle at like 600 with 741 cams

You revving that thing to 4900?

I agree you can get idle down further. I am going to bring my stops back a bit so shifting is easier

Right now still getting props right and drive hieght. They are new engines so I want to take it easy but I brought it up to 5000 and had more throttle left with 30 pitch sl4 by Hill Marine. The are basically a bravo I but stiffer. The boat had 28 bravo I props

I have 580ci solid rollers with pro systems 1200's. I have Idle at 1000 in neutral. With locked timing at 34 I drop to about 550-600 in gear. I have 1.36 gear and 34p 5 blades though. Idle is defintely higher once warmed up.... make sure you adjust mixture screws and idle speed once you get some heat in the engines. They will definitely be fat and idle high as a result if adjusted cold (on the hose).