post #1 of Old 01-18-2012, 08:20 PM Thread Starter
turtlerace
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Chevy 350, carb question

Presently on my CJ I have a little dilema and am looking for some advice.

The engine is a 350 that was built by a previous owner. What I know about it is that I was told it is .30 over. I do know it has a pretty strong cam, roller rockers, headers with dual exhaust, and an HEI ignition.

The Jeep specs are running 35s, 4.11 gears, with a Th350 transmission.

It has never been offroad and is just jacked up hotrod. No plans of chancing all the work done to it by wheeling it.


So here is the problem. It appears to be a race prepped engine. The intake is a brandless air gap highrise and the carb is a 750? Holley that has no choke set-up. It's just a straight race double pumper. I am wanting to change the intake/carb set-up to make it more driveable and lower it's mannerisms a bit. I have settled on a Edelbrock EPS manifold but am on the fence about a carb. I have a 600 Edelbrock and bought a new 600 Holley for this project but am questioning if I would be putting too small a carb on an engine built to this degree?

Thanks for the help and opinions!


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post #2 of Old 01-18-2012, 10:50 PM
jnicewan
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No choke and an airgap, I bet that thing sucks when its cold outside haha.
I highly doubt the engine needs a 750 carb, but if bolting carbs on from out of the box without tuning them to the engine the 750 may run a little better than a 600. I have mixed opinions about both the holley and edelbrock carbs, they are both good and can be tuned with some basic knowledge about carbs. I would probably say that an edelbrock is a little more user friendly for people that dont want to tune a carb or dont really know how, but the holley is easier to tune and make changes to.

Either carb will probably work fine for you as long as you can get it tuned properly, my advice to you would be to try to find a buddy or someone else around who knows a thing or two about setting up and tuning carburetors, a lot of times its just going to be a trial and error method.
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post #3 of Old 01-18-2012, 11:53 PM
1986cj
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Edelbrock performer and the 600 Holley should work real nice. A 350 with 30 over cleans up taper and now you have round cylinders, no real gain here, may have some gain with the cam, roller rockers less wear and a few hp gain, and every 350 sense around 77 has a HEI. Headers will gain you a few but I think a 750/780 double pumper is way over kill in less he dropped some big pistons in it.
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post #4 of Old 01-19-2012, 05:35 AM
1SASjeepster
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Go to Holley's web site. They have a "Carburetor selection" area that will guide you through a question and answer part. Your answers help them guide you to a correct carburetor selection. (This is based on your engine's build and such.) Unless you are racing, there is no need for a Holley "double pumper." That is just a waste of gas. You always want to stick with vacuum secondaries.

Holley also puts out a DVD which shows you how to positively tune your carburetor. Holley is one of the easiest carburetors to tune in the industry. You know, for all the names out there, Holley has been the dominant carburetor for the past century. It is because they are the best and most dependable. They totally dominate all forms of racing and competition, where carburetors are used over fuel injection. Those guys must know something...

Take care,

Check out "YJ V6 Conversion" if you want to see a frame up restoration of my 1992 YJ.

Check out "WWII Jeep Photos AND Restoration of..." if you want to see the original JEEP in action...
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post #5 of Old 01-19-2012, 07:22 AM Thread Starter
turtlerace
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Thanks for the help so far! Tuning isn't a problem either way. I am just wondering that a 600 cfm wouldn't be enough to feed the engine through the entire powerband since it is a street machine?
Would not be surprised if the engine were a stroker if I pulled it apart. It has tons of power and seems to be built very well.


BTW, just kicking around at Advance the other day and was reading their Holley boxes. The 600 vacuum seconday lists to be used on 150-350 HP engines. The 650 vacuum seconday states it is for a 150-300HP engine.
allllrighty then.....

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post #6 of Old 01-19-2012, 02:53 PM
kcaverly
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I'd think a 600 would be fine.

I had a 350 in my YJ with headers, performer intake, and edelbrock 600 and was very happy with the carb. The out-of-the-box settings were close, and with their manual I easily tuned it right within a couple tries. I did cheat a bit and used a wideband O2 sensor to make it real easy.

I never had to touch the carb after initial tuning and it ran well. Steep inclines did make it sputter but it never died and it hauled my massively overloaded trailer down the road fine.

Kevin

1993 Jeep YJ - 350 Chevy TBI, SM465, NP241, 14B SF LSD, 10B
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post #7 of Old 01-19-2012, 05:36 PM
chris142
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I have had 3 Edelbrock 600's (1406)and hated each one. They are simple to work on but even after 8 hrs on the dyno we couldn't get the jetting where it should be.

Plus when they sit 3 days or more the fuel either evaporates or drains down and they won't start w/o lots of cranking or pouring fuel into the vent to fill the bowls.
All 3 had this problem.

My experiance leaves me to recomend a 600 Holley. I run a 80457S on my truck now. Basically a polished Electric choke version of the 1850. Thats what I traded the 3rd Edelbrock 1406 for and it works flawlessly.
That Holley along with a Edelbrock Performer should work well.

BTW: The Holley gave me 90 ft lbs and 60 hp more than the Edelbrocks on a chassie dyno.
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post #8 of Old 01-19-2012, 05:47 PM
kcaverly
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The one I had was a 1405 and the jetting was simple, especially with the wideband. I forgot about it, but I did have the same fuel evaporation symptom as the last poster mentioned.

It never bothered me too much, it just took an extra couple seconds each time I started it. People have solved it in various ways, if you do a search for edelbrock fuel evaporation you'll find some.

Kevin

1993 Jeep YJ - 350 Chevy TBI, SM465, NP241, 14B SF LSD, 10B
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post #9 of Old 11-19-2012, 06:23 PM Thread Starter
turtlerace
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Update:
I went with an Edelbrock EPS intake and a 650 cfm Holley Street Avenger carb. Really happy with the set up!

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