1999 454 carb swap. best street carb, 600? 650? 750? CFM

[Nasty-LSX]

I have this carb now it it sucks really bad. Not even going to rebuild it.

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I'm not asking what carb I need I'm asking whats the best CFM for a stock hydraulic roller 454 with headers and full 2 1/2 in exhaust.
Came out of a 1999 2500 suburban. Vortec fuel injection converted to carb. Its not a race truck just a tow pig or commuter to where ever it goes lol. here is what it looks like in a video. I dont have pics. SQUARE BORE weiand intake.

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[carfanatic63]

People might disagree but a good quadrajet is hard to beat.

Flows 750-800 cfm, great street manners, plentiful, etc..

Been running one on my 454 for 10 years (intake, headers, exhaust) and it's been fantastic. Starts below freezing, hot, never bogs, great power and throttle response.

It's got better throttle response than most efi systems on new cars in my opinion.

Negatives, they are old at this point so some used ones are missing parts and/or warped. They are also difficult to set up compared to a holley or edelbrock but once they are dialed in, they are fantastic.

 

[Nasty-LSX]

Negatives, they are old at this point so some used ones are missing parts and/or warped. but once they are dialed in, they are fantastic.

I agree with everthing you said, but this is why i will not buy a used one. Just going to pic up a Eddy AVS II.

 

[ali_c20]

The AVS 2 has a great throttle response. I run a 500 cfm on my crate 350 in my K5. I calculated the cfm I need with a carb size calculator. I feared it would be to small but it runs better than ever before. Order a tuning kit with the carb.