That 670 would work for a stout 318. What makes your engine builder think it's appropriate for an engine only 2/3rds the size? What else is your engine builder recommending?

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Joshua

C'mon Josh, a 670 will work fine with 2.76 gears.

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Official Cookie and Mater Tormentor.

I give you all the proposed specs when the research phase is complete. Right now I am just giving you all some tid bits of the way things look like there heading. Keep in mind there is more going on here than just a 670 cfm carb. Part of the quote is including a two day dyno test that will be posted here. As long as the price isn't so high that it stops me in my tracks- pic, specs and dyno results will be yours for the viewing.

P.S. where going to use a 3.21 ratio

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67Cuda,FAST EZEFI,340cu,CR=10.25,RollerCam&Rocker (XR268HR,#20-810-9)(#1622-16)(EddyRPM#60779,#7576), (MSD6AL,#6425) A904, GearVendorsOD, 8 1/4,3.55:1, ClassicAir

670 will be suited to a gear more in the 3.91-4.30 range, with a 3000+ stall. It may work well on the dyno, but it won't work that good on the street.

If my cars main objective was still street oriented, I would have left the 390 on it.

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Official Cookie and Mater Tormentor.

While I'm happy for all you Holley guys out there, I specifically asked for information on Edelbrock's. I have nothing bad to say about Holley. If I wanted information on Holley's I'd have asked for it. I just want to get some input from some Edelbrock folks. Something to consider when answering posts. Just think about it.

I am very happy with the Edelbrock, right out of the box. However, in the never ending search for more performance, I was hoping someone might have a secret or trick of the trade!

Carburetors are like religion and politics, everybody has an opinion and we don't all always agree.

I'm jumping off my soap box now!

Maybe you aren't getting Edelweber answers because very few people run them?

Mikey Mopar has 1 of only 2 that I have ever seen at the race track.

I personally have tried to run one. I own 3. Back to back 500 Eddy against a 390 Holley the Eddy was a dog. If you already have a strip kit, that's the best you can do. What works/doesn't work on one car may/may not work on another. Go out and test.

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Official Cookie and Mater Tormentor.

These test strips. How do they work? Something that you put in your tail pipe and tells you if your running rich or lean?

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67Cuda,FAST EZEFI,340cu,CR=10.25,RollerCam&Rocker (XR268HR,#20-810-9)(#1622-16)(EddyRPM#60779,#7576), (MSD6AL,#6425) A904, GearVendorsOD, 8 1/4,3.55:1, ClassicAir

test strip? ....strip test? I think the moderator better step in.....

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Yeah....Im the one who destroyed this rare, vintage automobile.....

The old Carter "Strip Kit" is a box of jets, metering rods, and step up pistons springs. It's a carb tuning parts kit. Edelbrock has them for their carbs.

The other "strip kits" I'm aware of, but not familiar with, include a pole that runs from floor to ceiling.

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Joshua

I see this on motorcycle forums all the time (about carbs)

Person 1 says Brand B & C are junk, you need Brand A
Person 2 says Brand A & C are junk, you need Brand B
Person 3 says Brand A & B are junk, you need Brand C

Person 4 says you need fuel injection, while 1 -3 say no way.........


It always comes down to what the person making the recomendation usually works on................


I think Holley's, Edelbrock (carters), and Quadrajets are all tuneable, and can be made to work. Search the internet, read up, and understand how they work, then start to play........

On the primary bbl side:

Holley jets are easier to come by and cheaper, but I think are harder to get the exact mixture you want when you're playing with the power valve (not the power valve vacuum setting) because the jet controls the cruise mixture, and there's no way to easily size the power valve orifice.

The needles (springs for vacuum setting)for the Edelbrock and Quadrajets are more expensive, and a little harder to get, but you can get the mixture you want at both cruise and power. It's just a little trickier to understand than just swapping jets..

On the secondary side:

The Holley parts are again easier to come by, but since you don't have to worry about cruise and power settings here (it's all power), all carb types aren't too bad.

Then for serious tuning:

You start playing with air jets, forget all of the above carbs and get one that has everything tuneable (which means you better know what you're doing)........


To really tune a carb nowadays you really need a wideband O2 sensor so you can see what's going on. And I would recommend dialing in the primary side (dissable secondary), then doing the secondary for whatever you get.

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

There is no general perfect metering rod/jet/spring combination for the slant six (or any engine for that matter). Every engine is different and requires a different combination to run best. Although the out-of-the-box combination runs, there is some room for improvement.

While trying to figure out the best metering rod and jet combination might seem a bit confusing, it's really pretty simple. The fuel mixture supplied by any rod and jet combination depends upon the flow area between the jet and the rod. I've already created a table that lists the flow areas of both the economy and power steps on my Edelbrock Performer page.

While a chassis dynamometer would speed things up quite a bit, real-world driving really is the bottom line. As most slant six powered cars are generally used for everyday transportation, I recommend that you start optimizing the economy circuit. You start off by finding the flow area of the rod and jet set you currently have in your carb. Drive for several tankfuls of gas and measure your gas mileage. For the same type of driving, you should get measurements that are fairly close. Try a new rod and jet combination that has slightly smaller flow area than your current one. Drive through a few tankfuls and measure again. If your fuel economy improves, repeat with a smaller flow area. If your economy doesn't improve or you experience a lean surge, try using a rod and jet combination with a larger flow area. Use the softest metering rod spring for this testing.

Once you find your optimum economy flow area, you can then find the optimum flow area for maximum power. Find a seldom used straight section of roadway and measure your 0-60 mph time. Do a few runs to get a consistent time. For the same economy flow area, change to a metering rod with a slightly smaller power step diameter for a richer power mixture or a slightly larger diameter for a leaner mixture. Measure your 0-60 mph time again.

If you run out of metering rods of the same economy step diameter, you will need to check the chart to find another rod and jet combination with a similar economy flow area but either on the high or low end of the power step diameters that you require.

If you do NOT have intake manifold heat, you will require a richer power mixture to compensate for the additional fuel that falls out of the airstream during low airflows at wide open throttle. Metering rod #1458 provides the largest difference between the power and economy steps and is the last option to overcome an off-idle bog for those people wanting to run cold intake manifolds. While this metering rod may overcome the off-idle bog, it may be too rich for maximum power.

Once you have found your optimum metering rod and jet combination, you need to find your optimum metering rod spring. Start off with the softest spring and check if there is any hesitation during gradual acceleration. Progressively change to a stiffer spring until the hesitation disappears.

While people think that Holley carbs are easier to tune, I think that the Carter AFB/Edelbrock Performer is far better and there is never any chance of spilling gasoline during jet changes. Although the Edelbrock has a flow rating of 500 CFM @ 1.5"Hg, I would expect the flow rating of the primary side to be similar to that of the Carter BBD. During normal driving, it should have the same or better fuel economy than the BBD with the proper metering rods and jets.

Thanks Frank,
Nice write-up,appreciuate it!!

In all honesty this carb was pretty much a direct bolt in right out of the box.But tinker we must. After I asked the question for this thread I realized how everyone's car is set up different and to get the perfect answer would be impossible.

Somewhere along the line I heard disconecting the secondary's is a good way to dial in the primaries.Any thoughts?

Anyways thanks for your help.

JZ

Ideally, when you're finding the optimum primary power flow area the secondaries should be disconnected. Once you've optimized the primaries, you can reconnect the secondaries and do the 0-60 time trials again. However, you might need to reach higher speeds than 60 mph to get the secondaries set up. When you're cruising on the highway, the secondaries should be closed anyway so there is no need to disconnect them to find the optimum economy flow area.