Carb swap
KarbonXIII
11-13-2008, 12:53 PM
Hi I'm waiting for a call back from a guy selling a Carter AFB Competition Series Carb for 150$ with electric fuel pump, and I was wondering if Its the right move to swap out my beat up 4 barrel quadrajet on my 283 for the carter. I read on a forum that they're less fuel efficient than the quadrajet.
MrPbody
11-13-2008, 01:34 PM
That's true, AFBs aren't as efficient, especially the "Competition Series". They're designed for power production, not efficiency.
When properly built, there really is no better carb than Q-Jet. It can be very efficient, with the tiny primaries providing very good mixture velocity at lower engine speeds. It also can flow big volumes of air and fuel through those HUGE secondaries. Some of the later ones ('74-'80) need some primary circuit rework. The earlier ones need bowl work to increase the "stored volume" of fuel. The person rebuilding the carb must be qualified and experienced in Q-Jets. Borg Warner still sells high quality carb kits fro them, and the brass float. No matter what, CHANGE THE FLOAT! Any are probably fine with your smaller engine.
That being said, if you have a good "square bore" intake, the AFB can be made to run very well. If you need an adapter to install it on the Q-Jet intake, forget it. Adapters only get in the way. It will ruin any performance potential you may have.
One thing, DO NOT believe the AFB is "the same as" the Edelbrock. It is not. It is, in fact, superior to the E-carb. They just "look alike".
Jim
When properly built, there really is no better carb than Q-Jet. It can be very efficient, with the tiny primaries providing very good mixture velocity at lower engine speeds. It also can flow big volumes of air and fuel through those HUGE secondaries. Some of the later ones ('74-'80) need some primary circuit rework. The earlier ones need bowl work to increase the "stored volume" of fuel. The person rebuilding the carb must be qualified and experienced in Q-Jets. Borg Warner still sells high quality carb kits fro them, and the brass float. No matter what, CHANGE THE FLOAT! Any are probably fine with your smaller engine.
That being said, if you have a good "square bore" intake, the AFB can be made to run very well. If you need an adapter to install it on the Q-Jet intake, forget it. Adapters only get in the way. It will ruin any performance potential you may have.
One thing, DO NOT believe the AFB is "the same as" the Edelbrock. It is not. It is, in fact, superior to the E-carb. They just "look alike".
Jim
KarbonXIII
11-13-2008, 01:49 PM
so when we talk about less fuel efficiency, what are we takling here. By allot?
Automotive Network, Inc., Copyright ©2026