Carb selection?

[Jetaholic]

For that setup i would just run a single carb and good intake manifold.
I second that. I have pretty much a mildly cam'med 9.5:1 454 and am only running an Air Gap with a Holley 750DP and that's plenty for around 5300RPM. No need for the tunnel ram.

[justfloatn]

tunnel ram and oval port..bad combo
I third the comments. Sell the tunnel ram and get a Preformer RPM oval and 750cfm to 800cfm carb. IMO an open plenum oval would be better suited to the instant RPM gain of a jet. Victor or Torker.
Even if you're trying to sell. The turn key performance will sell the boat. And you'll save a couple of bucks on trying to tune two 600's to run correctly on that motor set-up.