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Discussion Starter #1
i have a 327 bored .30 would like to test out different carbs on it, i want to make it fuel efficient, because its gonna be my daily driver until I fix up my wagon. Does anyone have suggestion about what carb works best or most fuel efficient?

thanks
 

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Quadrajet is the most fuel efficient carb with it's small primaries but, if possible, if you stay out of the secondaries, you will be fine.

Remember, the most fuel efficiency you will ever get is by changing your driving habbits. Try and keep your RPMs under 2K and you have done the proper tune-up on the whole engine, (plugs, wires, etc, etc.).

This also includes that you have the correct tire psi on all 4 corners.

Edelbrock and Holley carbs are also pretty good but, you have to ensure that you don't get any junk into them.
 

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well id say no more than 600 cfm.. but i also have no clue what kind of cam your running or gearing in the trans/ stall converter etc.... 327 .30 over with mild cam.. no more than 600 cfm... but the best choice if you can keep your foot off the happy pedal is the quadrabog (quadrajet) as long as its rebuilt right and tuned to your application. If you think you can go grab a quadrajet off a 70 camaro from the boneyard and drop it on your mild 327.. its gonna be rich as a pig.... or worse...

if you cant build it yourself... find a good shop to do it for you... a decent quadrabob rebuild will cost less than a new holley and be more reliable to boot.
 

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Quadrajets only came in two sizes, 750 cfm and 800 cfm. It's really not an issue though due to their small primaries and vacuum actuated secondary air dump. GM had it right with these things. You'll get your best fuel economy and performance with a properly built and tuned Q-jet.
 

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Discussion Starter #7
what do you guys think about putting a two barrel edelbrock or quadrajet? they make them 500cfm and 300 cfm?

Thanks for the info, much appreciated it.
 

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need to buy the right "Performer" to match the base of whatever carb you choose.

personally i'd stay away from a 2bbl. the 4bbl will get you better efficiency...
 

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need to buy the right "Performer" to match the base of whatever carb you choose.

personally i'd stay away from a 2bbl. the 4bbl will get you better efficiency...
Yup! The small primaries will give you more low end torque and better economy, while the large secondaries and total CFM will give you performance when you need it. You're better off with the Q-jet than a two barrel IMO.
 

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Discussion Starter #12
ok 4 barrel it is, do you guys think the quadrajet is better than the edelbrock?
is the 500 cfm more efficient and the 600cfm?
 

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ok 4 barrel it is, do you guys think the quadrajet is better than the edelbrock?
is the 500 cfm more efficient and the 600cfm?
I won't say the Edelbrock is bad, it isn't. It's a Carter AFB from the 60's that Edelbrock bought the rights to produce. It was and is a very good carb. So is the Holley, although these two carbs can polarize people faster than politics.

You'll also find people who will tell you to throw the Q-jet in the dumper. In my opinion, those folks don't understand the carb and get frustrated with it. A properly setup Q-jet will generally give you better low end torque and better fuel economy, than either the AFB or the Holley. This is due to the smaller primary venturies. The smaller primaries create a higher intake velocity and this is what increases your low end torque. On the upper end, the Q-jet can be setup to outperform either of the other two, in similar CFM's.

Now, you should be able to pick up a good used Q-jet already set up for an automatic, or a 4 speed (whichever you need) for your application. Just find a good rebuilder or do a bunch of reading and do it yourself. The book to use as a reference is by Cliff Ruggles. It's considered to be the bible for Quadrajets.

My $.02 worth.

Chuck
 

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Discussion Starter #16
Thanks for the help guys, really appreciate it. It will be a q-jet and ill fefinatley chk on the specs.
 
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