Is a Carter 600 enough for a 455?

[iluvmy72]

I am wondering if my Carter 600 is enough for the big block 455. It was fine on my 350 but the 455....I don't know.

[JayDubBlazer]

I don't think it would be, I sure somebody will chime in with some more solid advice.

[dtlilly]

I wouldn't think so either, even if you jet the 600 up.

[67chevemall]

you need AIR on a big block!
Theres a 800 on ebay that is sweet! It is on another post here.

[screamin_c102]

NO, the CFM rating is the amount of air the carb can flow. The larger the engine displacement the more air needed to maintain a proper air/fuel ratio. Just jetting it up will increase the amount of fuel introduced into the engine, which will actually throw off the air/fuel ratio even worse.

Use a 750 CFM at least, or some of the older big block Quadrabogs were actually flowing 795 CFM.

The nice part about the Edelbrock/Carter carbs is that due to their variable venturi you can put a huge carb CFM wise on a smaller (or less needy) motor and jet it to run fine. As you change cam profiles and or CR you only need to adjust jetting.

Just my $.02

[72BLAZERDUDE]

You need at least a 750 CFM on that big block. I have a Edelbrock 1406 on my 307 and that is a 600 CFM carb.

[GMC AMI]

Originally Posted by iluvmy72

I am wondering if my Carter 600 is enough for the big block 455. It was fine on my 350 but the 455....I don't know.

NO

[flip66]

I was told by Edelbrock tech that a 600cfm is almost too small for a 396 so I would think that 600 would way to small for 455

[Bowtie67]

Interesting!! Nascar engines putting out considerably more HP & RPM and have restricted their cfm's to I believe under 500CFMs. I have a friend who has a built 383 with a tunnel ram running 1 Holley 390CFM 4 barrel and claims he can smoke the tires up while cruising and gets some pretty good gas milage in his 38 sedan. Although you wont reach any peak HP numbers with the 455 and this carb but if it is just a cruiser it may work fine, I would just bring it to someone who can make sure the air fuel ratio is proper.

[GMC AMI]

[QUOTE=Bowtie67]Interesting!! Nascar engines putting out considerably more HP & RPM and have restricted their cfm's to I believe under 500CFMs.

That would be to Level the playing field! If you put a 455 in a truck who in their right mind would restrict the BB like that! Sure it will run OK and so will a 283 CI. IMO go for at least a 750 double pumper min., 455 is no wimpy motor so FEED THE NEED!

[flip66]

True NASCAR does run on restrictor plates but the motors are built just for those races to do that they do not use the same thing on all tracks. I could be wrong but in the plate races they do not need much torque you need more CFM and fuel to get torque.

[68Stepbed]

It depends on how your 455 is built. Is it stock or modified? On a stock 455 it should be fine. If it is modified the 600 may not flow enough air and may starve the engine. It's not how big the carb is as much as how the A/F mixture is according to the amount of air going through the carb. I have an article that a guy states that he took the 390 Holley off of his 302 and put it on his 460 and the jetting was perfect. I have a friend that drag races a 66 Fairlane with a 390 and he uses a 600 Edelbrock. When he switched to a 750, it ran worse. The extra cfm's are only useful in high rpm applications. Carbs don't usually flow full cfm ratings at cruise speeds.

I would try the 600 and if your not satisfied then try something bigger. I would try a 750 vaccum secondary Holley or a 650 mechanical secondary.

Just my 2 cents. Let us know what happens.

[Hoods69BadBowTie]

Yeah, it really depends on how much you beef up your 455 or keep it stock. I think if its mainly stock a 650 would work good or even if its beefed up try running I think 670 but I can"t remember who makes one of the top of my head.
Later

[Tom]

NASCAR's get away with it because they make up for the power in other area's, namely heads and cam. Also don't forget they tune the intake for a supercharging effect, that helps up the flow of that little 500cfm carb a bit.

[ed455]

Some of the old Mopar 383's and 440's in the big Newporst and New Yorkers had Holley 600 carbs on them. Small carbs make for good low end power which is what those big barges needed.

[krue]

If you have the carb already, throw it on there. If it don't work you're not out anything.
If it does then you haven't bought a carb you don't need.

[Fred T]

For a stock engine, yes. Figures out to 631 CFM.
http://musclecarsusa.com/prods/carburetion/info.html

['68OrangeSunshine]

I used to have a 454 in a '67 K/10 Suburban. The PO put it in. Nothing fancy, just a junkyard transplant, so very likely stock. PO also had a Carter AFB 9635. It ran good so I didn't change it. The truck would cruise the freeway at 80 like a walk in the park. I always thought it was a 750 CFM carb, but it turned out to be a 625 CFM. The Edelbrock match is an EDL 1400.

[Ogier]

Originally Posted by iluvmy72

I am wondering if my Carter 600 is enough for the big block 455. It was fine on my 350 but the 455....I don't know.

Yes. This will work just fine on your 455.

I just love it when the "bigger is better" crowd comes out to play. Carberation is a science not a guessing game.

What will happen if you go much bigger than a 650 is the bottom end will get soggy and the midrange will seem to go away.

My personal favorite carb for the street is the good old Holley model 1650 600cfm universal carberator. They are extremely tune-able and contrary to popular belief, can and do get great milage when set up for the vehicle.

Incidently, I used to run this same carb on my Stage II 455 Buick and could smoke the tires till they blew without brakes... :hit2:

just my .02$

[GMC AMI]

Sure the motor would run with a 500 two bbl as well but who would want that? With a 455 you do not need to worry about bottom end with all that torque. If you think a Buick stage 1 or 2 came with a 600 from the factory you are sadly mistaken, they can easily handle a 750 double pumper. I ran a 455 Buick in a 80 vette body at the drags
and I never saw any soggy botom end or any lacking mid-range. The Vette ran 7.2 at 92 mph in the 1/8 th mile with stock 308 gears right off the street. Even Caddy BB's came with a much bigger carb than a 600. Now why would GM do that?

[Ogier]

True, the carbs that came out of the factory were _rated_ at higher CFMs, however, they were almost always Rochesters which are a pseudo-variable venturi carburetor and shares much more in design with the Predetors than with Edelbrocks, Carters, or Holleys.

The Rochester does _Not_ open up completely when you stab the throttle. It will only open as much as the engine can handle based on the amount of vacuum present in the manifold dictated by the RPM of the engine.

Thus, comparing the CFM rating of a Rochester and that of a Holley is rather like apples and oranges.

If you use a 750cfm Holley, Carter, or Edelbrock on a street driven vehicle you will likely have a soggy bottom end, crappy gas mileage and whitewashed cylinder walls.

Of course, I may just be blowing smoke out of my ass but having built in excess of 250,000 total horsepower in my life in engines ranging from lawnmower engines to 1200hp blown drag motors, I rather think that I am likely not.

I have said it before and I will again, Carburetion is a science. Bigger is usually not better.

Again, just my .02$

[GMC AMI]

The Rochester does _Not_ open up completely when you stab the throttle. It will only open as much as the engine can handle based on the amount of vacuum present in the manifold dictated by the RPM of the engine.

True on vac. secondary models, not mechanical secondarys which will open when you stab the throttle. I was using a 750 Holley double pumper on the 455 in the Vette.
It would truley pin you back in the seat from the so called soggy bottom end, maybe in your application, just was not true in mine.

[70c10]

I would personally run a 750. I have been in a few cars with stock 455 motors that had 750 carbs that would burn the tires off the car. I have a buddy with a 455 in his GTO and he runs a Dominator but that's another story

[crm318]

i think a good running qjet will suffice

[Ogier]

Originally Posted by Mike Files

The Rochester does _Not_ open up completely when you stab the throttle. It will only open as much as the engine can handle based on the amount of vacuum present in the manifold dictated by the RPM of the engine.

True on vac. secondary models, not mechanical secondarys which will open when you stab the throttle. I was using a 750 Holley double pumper on the 455 in the Vette.
It would truley pin you back in the seat from the so called soggy bottom end, maybe in your application, just was not true in mine.

Actually, even with the mechanical secondary Rochesters, the top set of butterflys don't open right away. They open with manifold vacuum.

Here is a page that talks about carburation done properly using a Holley. The same goes for Edelbrock and Carter carbs.

In the end, the person who owns the rig must decide what they want. There are questions that must be asked though before a proper recomendation can be made like how are you planning on driving the rig? Is this a race engine or a daily driver? Is gas mileage a factor?

With regards,