What size carb should the replacement be?

Carroll_B · May 9, 2002

I have a 79 Chevy C-20 with a 350 4 bolt main. The engine is only 6 years old with about 10K miles on it. I only drive the truck about 1500 miles a year. The quadrajunk carb has been overhauled once. I am thinking about installing a Holly carb and a new intake manifold, and perhaps headers as the truck idles very bad now, and does not have very much power. I have a 4:10 rear and use the truck to pull my 18 foot boat. If I decide to install a Holly carb, what CFM should I get? Should I get one that has vacuum or mechanical operated secondaries? Any sugestions on an intake manifold as to brand?

MarkD · May 9, 2002

I would go with a 600-650 CFM carb.

Demon makes what many consider to be the best out the box carburetor.

Carter makes some nice units as well. I think the AFB is a 625 cfm unit. I was very pleased with one on a '76 conversion from a six cyl to a 350/4 bolt. That was 15 years ago. Super Chevy magazine has a review of current aluminum manifolds. I believe it was Brodix that had the best performance. Definately get a dual plane manifold though. You risk losing too much low end torque with a single plane.

Torque Junkie · May 9, 2002

I agree. 600-650 is plenty for a 350.

I've been really happy with the Edelbrock performer combo for the intake and carb. You can probably pickup a Performer intake & 600cfm electric choke carb for around $350.

Good luck!

-Mike

Colorado Kid · May 9, 2002

I agree with what's been said. 600-650 CFM, Vacuum secondaries are what I would choose, but either will work (you just have to keep your foot off the floor until the rpm's build with the mechanical 2nds). Stick to dual plane manifolds on nearly stock, especially truck and towing applications (does Edelbrock still make the "Performer?").

Having said all that, you need to figure out why your stock 350 won't idle right and makes poor power. Plugs are the first suspects followed by vacuum leaks and other ignition problems. If it isn't one of those things you'd better check compression. If you dont get these things put right all the high performance parts in the world will just give you a more expensive engine that doesn't run worth a darn.

MarkD · May 9, 2002

Junkie,

Now that you mention it, didn't Edelbrock buy out Carter? The two carbs look an awful lot alike.

Torque Junkie · May 9, 2002

Junkie,

Now that you mention it, didn't Edelbrock buy out Carter? The two carbs look an awful lot alike.

I don't know who bought who, but I know my old Carter AFB and the Performer 600 electric choke I replaced it with are IDENTICAL.

-Mike

May 9, 2002

I've had real good luck in the past with the Holley 1850, 600cfm, vacuum secondary carb and Edlebrock Performer manifold.

Unless you really plan on winding that thing out, a 600cfm will be plenty.

I've heard nothing but good things concerning the Edlebrock carb from others, but I've never owned one personally.

Carroll_B · May 10, 2002

I will install new plugs. My son overhauled the quadrajet for me. It then cost me $300 to get it fixed right. The person who fixed the carb for me said my son adjusted items that should never be touched. I suspect there are some vacuum leaks also. Thought the new intake and carb would help with a little more power, solve the vacuum leaks, improve the idle, and make it run better. I'd like a newer truck, but since I use it so little I just can't justify making monthly payments. I'd rather put the extra money into my vette or towards a bigger boat.

Technicrat · January 3, 2003

I put an edelbrock edl-1903 carb on my '79

I had been having drivability problems and was failing my hydrocarbon emissions allowed = 350 ppm mine was 1500 ppm! I tried a "reman" from auto zone ( 3 times) couldn't get one that would run worth a Darn. I put the Edelbrock on and *poof* all my driveability issues went away. Note the engine is a just broken in goodwrench 350 4-bolt with a bumped cam

performer intake ( with egr) headers and duals through 2 cats and flowmasters. For a fully smog legal beast it runs pretty well. The next goodie will prbably be an MSD.

Ridinghigh · January 13, 2003

I'd recommend the Edelbrock 600-650 with the intake as well. I got a 4bolt 350 with those, headers, MSD ignition, some nice spark wires and plugs and a 4.11 and she gets up on it pretty good.

So thats what I recommend. Of course there are some better combos but I think thats some of the best bang for your buck. I have to work on a budget since im only 17 (almost 18 ha!).

Anywho there are my 2 cents.

ClipperSkipper · January 21, 2003

Jees you're going to hit me over the head for this one: I love most Rochester four barrels! Get an older Rochester carb (4GC or MV) with a divorced choke or electric choke ala Volvo-Penta marine engine (mid eighties) no ports easy rebuild waht a streetable engine you'll find! Loose the Edelbrock carb they cannot fix the off-idle power lag and surge.

Have a great one!

fortop · May 17, 2003

clipper skipper - Where would I buy a new GM quadrajet for my 83 Chevy 3/4 ton 454? My original carb is operating badly, and I have never had good luck with rebuilt carburetors. I used to buy Carters, but the retrofitting to the stock manifold was always a hack job, and this 83 has a ton of emissions junk to hook up. ???