What size Carb should i get for my 305?
I have the stock Quadrajet on it now, but want speed!!!! Also, Holley or Edelbrock, (Demon to much $$$)

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--Steve S-- 84 Trans Am 305 HO 5 speed, completely stock will soup up when i get some $$$$$$$$$$

 

The q-jet is not what is keeping you from attaining the desired speed. Your problem lies with the peanut cam, low-flowing heads, restrictive exhaust manifolds, restrictive y-pipe, low-flowing catalytic convertor, restrictive exhaust, and low-speed oriented intake. If you have a single-snorkel air cleaner, ditto.

You can make that 305 run by changing everything that comes after the q-jet. Just putting a Holley, Edelbrock, or Demon on it now would not make it a bit faster. The q-jet is the one thing you should keep!

See the tech articles for making the q-jet even better.

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82 Berlinetta, orig V-6 car, now w/86 LG4/TH700R. 2.73 unlimited slip. Cat-back from '91 GTA, Accel HEI SuperCoil. AMSOIL syn lubes bumper-to-bumper. Daily driver, work-in-progress (LB9 w/ZZ3 cam, TBD heads, exhaust, paint, etc.).
57 Bel Air, my 1st car. 0.030 over 396, Weiand Action+, Edelbrock 1901 Q-Jet, Jacobs Omnipack, 1-3/4" headers, TH400 w/TCI Sat Night Special conv & shift kit, 3.08 10-bolt, AMSOIL syn lubes bumper-to-bumper. Best 15.1 @ 5800' Bandimere. Daily driver while Camaro was being put together.

 

Wow

 

five7kid is right about there being many other restrictions on that engine. But I'd list that Q-junk right up there with it. Get a Holley 600.

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"American made baby. 100% American iron. The muscle among the masses. My hero. Yep, you can take your ergonomically designed, space age, computer controlled, 4 door, cup holding map lighted split double wishbone split fold down retractable cargo covered moon roof piece of transportation and keep it. For I have felt the thunder. And I know the difference!"
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Florida Thirdgenners Message Board
ICON Motorsports

[This message has been edited by Jester (edited November 29, 2000).]

 

I made a noble effort to keep my q-jet, but I ended up with a Holley. I would have gone with a Demon, but the Road Demon is too small for my application, and the Street Demon is too expensive after you add up fuel lines and e-choke to the $415 pricetag.

Look at the article by Ed on th main page. It is an excellent resource! Most of the mods are free too.

I agree with the others, there are many things you should do first before tossing the q-jet. Intake manifold is a great start. They run about $100 for a Performer and it helps a lot. An open air element and 1.6 roller rockers are also things that help a lot. A 3" full exhaust is a great thing to do too before having to tear into the engine (cam and heads) or going with a 350. All those mods can also be transfered over to a 350+ SBC if you choose to go that route later... heads won't, cam might not either.

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1984 z28 w/ a 357 cu in. monster engine which is looking like the posterchild for Edelbrock... all the suspension stuff... 9-bolt posi disk is in... K&N filter... 93 octane...

-=ICON Motorsports=-

[This message has been edited by Biochem (edited November 30, 2000).]

 

they are right, the Q-jet is the least of your worries. Besides, you will not get as good of milage with any other carb. I had a buddy with a slightly modded 350ci and the stock mechanical q-jet. He switched to a street demon and did not even pick up a tenth is the quarter.

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1983 Camaro Z28
Goodwrench 350ci V8, Edelbrock TES Headers, Flowmaster Catback, MSD 6al and Blaster 2 coil, Edelbrock Performer intake, Edelbrock Performer 600cfm carb. T5, 373 rear, Eibach springs, Cervin Vega speakers, Rock. Fos. Sub, Pioneer CD,
email-chris4421@hotmail.com
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"I used to be a Mustang Guy! I didn't know the power of the dark side!!"

 

Assuming a 1.5" vacuum drop across the carb and 100% volumetric efficiency, here's the formula:

engine CFM = (engine CID x max rpm x volumetric efficiency)/3456

So, if your 305 is at 5000 RPM and is completely filling the cylinders (not with those sorry heads!) then you only need a 442 CFM carb! Surprise!!

Technically, a big two barrel could feed your 305! Wow! A Q-Jet is MORE than capable of feeding that 305!