Taking power out of motor?

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Burban

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Yep, and the engine needs to be properly tuned. A 400 hp 350 that is built for lower end and midrange can get just as good mpg as a stock motor. Possibly even better if you keep your foot out of it.

Why the heck did they make carbs like the Economaster then?

My understanding was a typical engine at about 85% Volumetric Efficiency was usually wildly over carb'd. More air means more fuel.

https://www.summitracing.com/expertadviceandnews/calcsandtools/cfm-calculator

For a 355, unless your exceeding 5000rpm, 450cfm is plenty? If it's a lugger anyways, if you like to scream it to redline, then maybe more carb is good? I know the old 350 powered bread trucks used to use the Economaster and other small carbs, they weren't setting any speed records, but step vans are designed to haul heavy loads.
 

highdesertrange

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yeah but look at the primary bores on the Qjet and the bores on the 2bbl. the Qjet has smaller bores so less CFM if you stay out of the secondary's. the 2bbl getting better fuel economy is a common misconception. highdesertranger
 

74 Shortbed

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For mileage you cannot beat a Q-Jet carb period..
 

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