Thread: what carbs for my 427 w/tunnel ram boat?

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I need to get new carbs for my boat and really don't know what would be best. The motor is a 427 with a full race cam with a tunnel ram intake. Can anyone give me some advice?

We'd need quite a bit more information to even hazard anything more than a rough guess.

Pump or outdrive? What impeller trim (AA, A, B, etc [no, not bra sizes]) if a pump? If outdrive then type, pitch, wheel dia, cup, single or dual prop?

Ford or Chevy? Not much impact but good to know. What is a "full race cam", what cam grind or at least lift/duration numbers? What compression ratio, what heads, etc?

Size of boat and displacement?

What carburetion are you running right now - you need to establish a baseline - manifold type, CFM, etc?

What RPM at full throttle with the existing setup, how quick before the hull dries out? What is the engines design redline?

How is the boat used - does the wife or girlfriend operate it as well as you so it needs good idle and low RPM qualities? (Not being sexist, I have experienced this firsthand)

Lacking any other information a pair of 600 vac sec Holleys would work just fine for all around play work. Thought about an EFI setup instead?

Regards, Mark

I would definately go with vac. sec. carbs. Without more detail's it's hard to tell you how big to go on carb's . Try this, take your 427 cubic inches times your max R.P.M.'s divide by 3456 then times it by your V.E. which on most high performance motor's is 85 percent ,or.85. Example 427X8000= 3416000 divide by 3456=988.43 X .90=889.53 C.F.M.'s