Thread: Edelbrock or Holley?

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I have a 355 chevy SB with a 270 INT./280 EXH. cam, Edelbrock Performer RPM intake, and headers. Some minor work has been done to the heads, but nothing to extensive. I have a Holley 600CFM marine carb. Could somebody tell me if this marine carb would work and if it would even flow enough CFM's. Or should I get a Edelbrock 750CFM, or would that flow to much air. Any help would be appriciated. Thanks, Bobby.

Ditch the boat carb and get a road demon

http://store.summitracing.com/defaul...5+street+demon

625 road demon or 570-670 Holley Street avenger, both are great for your needs and have the option of electric choke, easy to tune and offer great performance...if it was me I would get the demon, but it will likely cost more...up to you I guess.

If your driving on the street and plan to use it as a daily driver, use the Edelbrock performer 600-750. But it seems to me that you havent done too extensive work to warrent a HP carb. Toss the Marine carb or e-bay it, and decide what your going to do with it. If you plan to build it up further, buy the Holly/Demon carb and save your money.

Bob, how much RPM do you see with this motor ? or intend to see ?
5500 RPM ? than Id use a 600 cfm.. personally I like Holley over Edelbrock.
6000 RPMS ? than I like the 625 Road Demon from Barry Grant
6500 RPMS ? probably not based on the info you gave...but just in case...Id use a 670 Holley Street Avenger

This motor is going to be a daily driver and will probably never see more than 6000 RPM's. From what people are telling me, the Holley is a better way to go. Should I stick with the spread-bore holley, ex. double pumper, or should I go with the square-bore. Does the square-bore that some holley's use and that edelbrock uses cause for poor fuel economy and/or poor performance. Would mechanical secandaries over vacume secandaries affect economy and performance? Also, does anybody know if the stock Q-jet is a carb worh modifying to use with the stock iron spread-bore manifold on this particular motor. Money is an issue, so would I be wasting my time or should I save money to buy aftermarket parts, like a holley with a spread-bore intake.

Originally posted by bobpar
This motor is going to be a daily driver and will probably never see more than 6000 RPM's. From what people are telling me, the Holley is a better way to go. Should I stick with the spread-bore holley, ex. double pumper, or should I go with the square-bore. Does the square-bore that some holley's use and that edelbrock uses cause for poor fuel economy and/or poor performance. Would mechanical secandaries over vacume secandaries affect economy and performance? Also, does anybody know if the stock Q-jet is a carb worh modifying to use with the stock iron spread-bore manifold on this particular motor. Money is an issue, so would I be wasting my time or should I save money to buy aftermarket parts, like a holley with a spread-bore intake.

im sure nobody is going to agree with me but if money is a issue id get me a good q-jet , not much you can do to it unless you can still get some dif. metering rod, but it not a bad st. 350 carb. youre not going to impress anyone with it though

LT-1 I agree completley, I love a good working properly tuned Q-jet.

Originally posted by bobpar
I have a 355 chevy SB with a 270 INT./280 EXH. cam, Edelbrock Performer RPM intake, and headers. Some minor work has been done to the heads, but nothing to extensive. I have a Holley 600CFM marine carb. Could somebody tell me if this marine carb would work and if it would even flow enough CFM's. Or should I get a Edelbrock 750CFM, or would that flow to much air. Any help would be appriciated. Thanks, Bobby.

From what you wrote I would have to say that you are looking to overflow your mechanicals. You don't need a 750CFM anything unless you are going to beef up your motor later on.

Personally I'm in agreement with everyone else on the Marine carb. Ebay it. Get something useful out of it.

The Edelbrock you should shelve until you have your motor more beefed so it will run every bit of fuel the carb dumps into it.

Cause right now your motor will not burn that much fuel unless you've enlarged the Valves in your heads and added a beefier cam as well as increased your compression ratio.

It's just as bad to overfeed the motor as it is to starve it.

If you are running a stocker I wouldn't put much into it.

550cfm would be plenty.

If it's just a step up then...

600cfm

and work up 50cfm for each step of cam change that changes the duration.

Also Edelbrock is a decent Carb. There is noting wrong with it.

Unfortunately you can't tune the thing, like you can a Holley, Demon or Predator.

But you won't need any of these if you plan on running pump gas exclusively and if you want to keep your ride a dailey driver.

If you want to run the tracks more than the street I would suggest to use a squarebore carb for the street that you can yank and put on a tunable Holley DP. It's a decent carb, you can change the bowl size to accomodate the demand as well as change jet sizes to increase the flow rate.

Thanks for all your help guys, but I have another question. Should I run a spread-bore or square-bore aftermarket intake manifold. Is bad to mix a spread-bore intake with a square-bore carb or vice-a-versa. Of the above choices which would give me the best economy and performance? Also does anybody know if shory hot rod headers will fit a 67 Chevy C-10, or should I get long dump headers instead. It does sit a little lower than normal so I am afraid that the headers might be to close to the ground if they are the long dump kind. Thanks Bobby.

quote from moparmadman.... Also Edelbrock is a decent Carb. There is noting wrong with it.

Unfortunately you can't tune the thing, like you can a Holley, Demon or Predator.




im going to have to disagree with you on this one moparmadman, but you can buy anything you need to fine tune that edelbrock, you can change everything on it other than the size of the venturi. i agree with you on the 750 being to big though

Originally posted by lt1s10
quote from moparmadman.... Also Edelbrock is a decent Carb. There is noting wrong with it.

Unfortunately you can't tune the thing, like you can a Holley, Demon or Predator.




im going to have to disagree with you on this one moparmadman, but you can buy anything you need to fine tune that edelbrock, you can change everything on it other than the size of the venturi. i agree with you on the 750 being to big though

You may be right. But I've yet to see anything available other than a complete rebuild kit.

Also you can't change or add to the bowl size in the spreadbore configuration. It's all inernal. So in the Rottenchester configuration you wouldn't get much that is upgradeable if anything.

I just looked through the current JEGs catalog and nada.

Now in the Squarebore or Holley config, I must admit that I'm not as familiar with them so I might have overspoke my opinion. They may have the upgrade parts or you might be able to upgrade with Holley components.

One Carb that was COMPLETELY left out of this debate was the Carter. I know that you can upgrade these. Even the spreadbore although not able t o get a bowl resize kit you can rejett them. They are definitely worth the money if you can find them. I think Summit carries those.

Thanks for agreeing htat 750cfm is too much carb for his app. though.

Originally posted by bobpar
Thanks for all your help guys, but I have another question. Should I run a spread-bore or square-bore aftermarket intake manifold. Is bad to mix a spread-bore intake with a square-bore carb or vice-a-versa. Of the above choices which would give me the best economy and performance? Also does anybody know if shory hot rod headers will fit a 67 Chevy C-10, or should I get long dump headers instead. It does sit a little lower than normal so I am afraid that the headers might be to close to the ground if they are the long dump kind. Thanks Bobby.

If you run a spreadbore stick with a spreadbore manifold and vice versa squarebore.

It doesn't make any difference if you have a quality adapter if one is available. It all goes in the same place, right?

However if you are wanting to stuff it all under the hood you have to account for the extra height that an adapter would add.

Again everything is reletive. Basically you're going to have to put it all together from the carb up and measure the height to the top of your Air Cleaner. If you feel good that the added height won't make any difference no big deal to run an adapter.

It won't hang up any fuel molecules or create problems as long as you use the two gaskets needed.

As far as headers go I haven't done this yet but I would say that it depends on what's available #1. A C10 should have quite a bit of options unless it's a 4x4.

I have a heavy 1ton and it had full headers on it right to the pipe collectors.

So if it's a standard C model you can put most any headers on it.

However I would suggest that you use a double heat shield on your starter. They make a sleeve to bolt tween the solenoid and the starter body. After you have that on I would also suggest that you use a decent starter wrap shield as well.

I changed mine over from headers to stock manifolds as our rough rural road broke the welds in the right header. I didn't do the wrap and I'm still having problems. That damned starter is solenoid up and so it takes alot of heat making long distance travel in the flat bed a pain in the okole.

If you want to install the shorty style they work good too. This is probably what I'll have to do with my Savoy. I haven't measured the size difference between the flattop 6 and the 318/340 but I'm guessing that I'm not going to have much room for full headers and so far I haven't seen a full size offered for my old Plymouth.

Though I did find out that FatBoys makes a subframe for my year of car.

Nothing wrong with the Edelbrock carb, Holleys are just more popular, like Chevys. Not better, just more popular. Edelbrocks are just as tunable as Holleys. In fact, the Carter AVS was the simplest carb to tune all-around, and Edelbrock just came out with their AVS. With the AVS you can do most of your carb tuning without ever opening the carb. The marine Holley is nothing but a run-of-the-mill vacuum-secondary Holley design so the bowl vents don't spill over. Nothing but fire-protection.

Originally posted by Streets
Use a Predator and sh*tcan all the rest of um!!

streets, 1/2 of the time i cant tell when youer joking or not but i have run the predator (2 of them) on a 350 blown drag car and on a 406 round track car and they worked great. people around here didnt know what it was. it really work good with the blower motor.