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1987 ChrisCraft 333 454 350 carburator specs

C

cruisers00

Regular Contributor
"Have a pair of Quadrajet, Roc

"Have a pair of Quadrajet, Rochester Carb. thinking about replacing with Edelbrock carb. Is anyone knows what CFM I need? was suggested 750 cfm, your expertise will be appreciated. Thanks
Henry G"
 
Agreed. The larger sizes just

Agreed. The larger sizes just cost more in purchase and gas.

Jeff

PS: Edelbrock makes an adapter to mount them on a Q-Jet intake.
 
"Not only that, I believe thos

"Not only that, I believe those carbs are very easy to rebuild and more importantly, easy to fine tune. They have a "textbook" response to fine adjustments."
 
"I'm still asking that Que

"I'm still asking that Question Jeff.
Why would a 454, turning 3000 RPM, use more fuel with a 750 cfm carb, than it's sister engine turning the same RPM with a 600cfm.

The volume of air being swallowed would be the same,
why wouldn't the amount of fuel be?

Fred 156-M

P.S.
Don't thing about switching to Edelbrock carbs, "Just do it"."
 
"Fred, that exact engineering

"Fred, that exact engineering problem describes how to design a great carb. Everything being equal, it is easier to provide the "correct" fuel, when high velocity air provides a high pressure gradient. Smaller bore passage = higher velocity. I'm not saying the 750 can't give you equal fuel burn, only that it is harder for the large carb to work the entire flow range with its larger bore. If you want optimum WOT power, by all means, get the big carb.
By measurement, each of my 600's delivers 24gph at 4500 rpm. I'm good with that at the top end. And, I don't spend much time there, either..."
 
"Dave's right on top of th

"Dave's right on top of the physics...

another way of looking at it is that, out-of-the-box, for a generic calibration, the larger flow carb will provide a richer mixture to satisfy the higher flow.

You can go in and adjust the components in the larger carb to provide the calibration you want, up to a point. The smaller carbs are more efficient in their use of the primary circuits and provide a better solution."
 
"Mark;
You sound like the hig

"Mark;
You sound like the high school counter person at O'rileys "<font color=""0000ff"">provide a richer mixture to satisfy the higher flow.</font>"

I'm pretty sure that it don't mater weather you got a 305 or a 454, regardless weather its running at 1500, or 5000 rpm, they all run best at the same air/fuel ratio.

However, I do agree on the "<font color=""0000ff"">The smaller carbs are more efficient in their use of the primary circuits and provide a better solution.</font>" point.

And Henry: my advice to you is, get the 600's , We've been hashing this out a long time & they are the carb of choice. No one has ever regretted making the change.

Fred 156-M

(Only 39 days till Augusta, MI
http://www.michiganhydroplane.com/Members.html"
 
"Fred:

little brutal there

"Fred:

little brutal there though your point has merit. Perhaps something like the larger carb has to provide more fuel to satisfy the
WOT requirements. This will produce an overall fuel delivery curve that is richer than the smaller carb for a given engine.

The bottom line is you need to adjust each carb to each engine it sits upon if you want best economy. And this is much more than jets.

If Henry gets those 1409s & wants to donate his Q-jets to my "hands-on learning center", I can make good use of a few more cores."
 
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