Why everyone carb swapping?

[Pinger]

Worth remembering that a (any) fuel injection system that doesn't depend on a restrictive venturi for metering will have superior airflow potential over a carb.
Fuel injection - initially in the pursuit of more power then, improved emissions (and durability). No DFV ever ran with carbs.

 

[Erik the Awful]

No I don't imagine a Q-jet would keep up with that but two of them may have a fighting chance.

There were some larger Quadrajets. Cadillac Quadrajets were 795 CFM and were a lot more common than the 805 CFM Buick Quadrajets. I think they're all hens' teeth now, though.

 

[Supercharged111]

There were some larger Quadrajets. Cadillac Quadrajets were 795 CFM and were a lot more common than the 805 CFM Buick Quadrajets. I think they're all hens' teeth now, though.

80s trucks got 800cfm units, I have one on my dad's Monte. It originally had a MKIV 454. Of course it doesn't rev nearly high enough to need it, I believe it was just the primaries that were bigger so that may have been the real reason it was used.

 

[TonyM]

Just gonna leave this here

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[Scooterwrench]

Just gonna leave this here

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Which one is you?

 

[Scooterwrench]

I have one of the old Vibration Tachometers for those and where I usually ran the Briggs is around 2,800 rpm.

I ran mine 6200-6500. When I first started racing those motors I never would have thought they would turn that. I flogged 'em and rebuilt them over and over never slung a rod in the first one. Tough as nails!!!

 

[99xcss4]

Just gonna leave this here

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Which one is you?

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[Scooterwrench]

80s trucks got 800cfm units, I have one on my dad's Monte.

Those are the carbs I search for. The numbers always start with 17. GM put them on just about everything after '75(I think). What they did to match airflow with engine displacement was to adjust how far the secondary throttle and air plates would open. There was other things they did like air bypass ports, air bleeds and of course jets and needles. As EPA requirements got tighter needles got fatter.

 

[Scooterwrench]

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Those were good carbs for smaller displacement engines with mild cams but the later version was better for engines with higher flow numbers. IIRC those carbs flowed about 650 CFM.

 

[99xcss4]

Those are the carbs I search for. The numbers always start with 17. GM put them on just about everything after '75(I think). What they did to match airflow with engine displacement was to adjust how far the secondary throttle and air plates would open. There was other things they did like air bypass ports, air bleeds and of course jets and needles. As EPA requirements got tighter needles got fatter.

they can be had new or reman but you will pay https://www.summitracing.com/search...r-flange:rochester-large-4-barrel_spread-bore