carburetor #4:Edelbrock/AFB

When i was building my first drag motor, my 462 olds big block, i went with an edelbrock 750 cfm carb as well. off the top of my head i thing the referrence number was a 1407. these to be honest are a good carb that is a lot easier for tuning over the other two brands, but neither the mileage of a q-jet or the power of a holley. they are a good carb for the right application….and budget.

the Edelbrock carb that we see now days is basically a variation of an old carter/AFB design from years past. Hell even the new thunder series AVS carbs are nothing new they were around many years ago. the AVS stands for air valve secondary and fucnctions similar to the rear barrels on the other two brand of carbs i mentioned. never really messed with one yet so that’s what i know on em.

the AFB is very tuner/user friendly. it has float bowls on either side but only one fuel inlet. on either side of the air horn there are small taps which you can losen and pull the power valves out to change the metering rods. metering rods are the calibration over jets with these things, although you can remove the air horn and change the jets. the front barrels do most of the work and have the metering rods, the rear barrels are basically along for the ride and have an air valve with a counter weight rather than any kind of a vacuum signal to aid in preventing any kind of a lean condition when you bury the throttle.

for the street, putzing around on the weekend this is a great carb. the carb comes with a book that outlines which size rods/jets to install to change your mixture. the power valves also have different rated springs you can buy but i have found it doesn’t make that big of a difference. the baseplate is a squarebore pattern identical to the holley, but the smaller carbs like the 1405 have smaller primary’s and can fit directly to a spreadbore intake on occassion without a spacer or adapter. not always the case.

that bad part of these things is that when you crack the throttle wide open, especially at the drag strip, it coughs…..and the rear barrels don’t seem to do much. them weighted air valves on the back aren’t worth a shit for racing. ran great around town though. i literally toward the end just ran on the front barrels of the carb and left the rears unhooked….and only lost a 10th in the 1/4 mile!! that’s sad….and i tried every damn calibration i could get my hands on.

for derby, i have never tuned or ran one. i have been told if you install the off road kit into the float bowls they work well. i would still run it on the front barrels only. now all this being said, when you weigh in the price and ease of service, i wouldn’t be afraid of buying one for the right use. for racing or serious street-strip horsepower, you go another direction.

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