Proper CFM carb for 330hp 454?

I have a garbage automotive Q-jet on the 454 in my Checkmate.

Not sure of the exact mods that the boat has because it's a bit of a basketcase that I picked up cheap.

Without ripping it apart, it seems to me like a motor with a midsized cam and a Weiand intake and not much else interesting...

I'm thinking a 600 cfm edelbrock?

Thoughts?

Quote:

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Originally Posted by baddogz28

I have a garbage automotive Q-jet on the 454 in my Checkmate.

Not sure of the exact mods that the boat has because it's a bit of a basketcase that I picked up cheap.

Without ripping it apart, it seems to me like a motor with a midsized cam and a Weiand intake and not much else interesting...

I'm thinking a 600 cfm edelbrock?

Thoughts?

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Depends....on some 454's with mods i would say 750-800 ?!

But if very mild 600-650 should be fine .. IMO !

Quote:

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Originally Posted by DAREDEVIL

Depends....on some 454's with mods i would say 750-800 ?!
But if very mild 600-650 should be fine .. IMO !

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x2 Make sure you get the Marine carb.

Although it probably doesn't need the cfm the 750 Edelbrock will work fine right out of the box. The 600 is set up for a smaller motor and will usually run too rich on 454 down low and at cruise especially with the small heads and cam. It's easy to rejet but I wouldn't bother, just chuck a 750 on there and let er rip. :cheers2:

I have a like brand new Holley 600 cfm vac performance carb dual feed carb rare with metering blocks front and rear and jets frt/rear too 175.00 plus shipping.
Here is the carb
http://www.michiganmotorz.com/holley...rrel-p-97.html

750

Quote:

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Originally Posted by HaxbySpeed

Although it probably doesn't need the cfm the 750 Edelbrock will work fine right out of the box. The 600 is set up for a smaller motor and will usually run too rich on 454 down low and at cruise especially with the small heads and cam. It's easy to rejet but I wouldn't bother, just chuck a 750 on there and let er rip. :cheers2:

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I agree. We put a Eddy marine 750 on my buddies 330 that is pretty well stock with an intake and I think a slightly larger cam. It runs perfect with about 5 minutes of tuning. IT was only like $300 or so from summit too.

650 if it will remain stock. 750 will work now and grow with you later too.

Personally I'd also opt for mechanical vs. Vac. They have always started so much easier for me it is worth any fuel consumption increase.

750cfm was the stock cfm on the Qjets and Weber carbs on the Merc(non merc racing) 454/502 engines.

Thanks for all the input guys! I'll keep you posted on how she runs with a 750.

Chris

Quadrajets are good carbs, unless there is something wrong, and can support a 454 making 400+hp. I dont think you'll get any more power or fuel effieciency by going to a holley on mild 454. The accelerator pumps tend to take a crap on them, causing a off idle bog. Cheap fix. There is also high perf rod hangers, needle and seat assemblies, and stuff for them.

Back in the day i had a 400CI Pontiac in my old T/A. Bought a 750 holley brand new for it. After a while, ended up going back to the stock rochester and response, power, driveability and mpg was better.

My vote would be to have the quadajet freshened up!