cutting carbs
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Posting Guru
Joined: Apr 2004
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From: Lewistown, PA
cutting carbs
For those of you running bigger carbs (500cfm+) what do you have?
I know the Holley 390 is popular for stock to slighhtly modified, but what about the more radical stuff? Is a Holley 570cfm street avenger a good choice(assuming that all else is compatible)? Or would an Edelbrock 600 crm be a better choice?
I know the Holley 390 is popular for stock to slighhtly modified, but what about the more radical stuff? Is a Holley 570cfm street avenger a good choice(assuming that all else is compatible)? Or would an Edelbrock 600 crm be a better choice?
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Joined: Jun 2003
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From: shepherd
i used the avenger 570 on a 5.0 mustang 5 speed for a day and it was way better than my edelbrock 600, it revved faster and idle was better even with the cam i had, keep in mind that my motor had everything aftermarket but heads, so it may be a lot different on a stock 300.
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From: Colorado
"Regardless of ALL of the evidence to the contrary, a lot of carburetor buyers "psych" themselves into believing that bigger is better." M. Urich (Holley Carburetor Handbook).
In an 85% VE (high performance) 300 I-6, the Holley 390 will carry you to almost 5000 rpm. 570 cfm get's you near 7000 rpm, & bump that to almost 8000 rpm with a 600 cfm. If you're not going to USE those high rpms, well, at least you'll have a BIG carburetor, and poorer acceleration times.
If your 300 is really THAT high performance, do yourself a favor, choose your red line, and buy the carb that fit's best, and don't fall into the "bigger is better" carburetor trap.
Give me your red line - I'll do the charting for you...
"You'll be happier with the SMALLER carburetor nearly every time." (M. Ulrich)
In an 85% VE (high performance) 300 I-6, the Holley 390 will carry you to almost 5000 rpm. 570 cfm get's you near 7000 rpm, & bump that to almost 8000 rpm with a 600 cfm. If you're not going to USE those high rpms, well, at least you'll have a BIG carburetor, and poorer acceleration times.
If your 300 is really THAT high performance, do yourself a favor, choose your red line, and buy the carb that fit's best, and don't fall into the "bigger is better" carburetor trap.
Give me your red line - I'll do the charting for you...
"You'll be happier with the SMALLER carburetor nearly every time." (M. Ulrich)
Elder User
Joined: Mar 2003
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From: Colorado
Under 5,000 RPM - yes! Unless you're getting 90% VE - or better...
Like I said - if you're that serious about high performance, you'd BETTER read ANY carb book on size/selection, or you'll probably be wasting your hard spent $$$$.
Like I said - if you're that serious about high performance, you'd BETTER read ANY carb book on size/selection, or you'll probably be wasting your hard spent $$$$.
