Carb Replacement

[maximus]

I happen to have a 625-650 CFM electric choke Holley laying around and was wondering if it was a good choice for my now stock '77 L-48? And after I install a Performer intake,Dynomax Cerami-Coat headers,and Flowmasters? Suggestions and advice,please? Thanks

 

[AUSSIEVETTEMAN]

Don't know if this is any help.

Maximus,

I had a Holley carb on my 81 Coupe here in Oz. Worst dam carb ever!
We replaced it with a 795 CFM Edelbrock QJet carb and now she really boogies!!!!
Bought it on Ebay for $330 US brand new.

Cheers and good luck with your carb,

Tony

 

[maximus]

Wow! You shot that Holley down quick:eek That bad,huh? I heard good stuff on a couple responses,on another forum.I was thinking Edelbrock or Barry Grant for my '78 Olds.....

 

[AUSSIEVETTEMAN]

Holley Carb

We just had no luck tuning it.
It would cough and splutter in the morning, which is typical for a Holley and it had a massive flat spot when you tromped it.
Some guys can get them to go good, we just had no luck.

The Edelbrock QJet, on the other hand, is a exact copy of the Qjet carb that our 81 Coupe came out with and has the same airflow of 795 CFM.
This carb is great and I haven't got the choke hooked up, but when you go out in the morning, all you have to do is give her one pump and crank the engine. She fires first go and doesn't stall at all. She never misses a beat.
She also sits on an Edelbrock Performer manifold.

Maybe you might have some luck tuning your Holley though.

Cheers

Tony

 

[KenSny]

Well, I've run Holley's for years on various rods. Never had those kind of problems. I currently run a 675 Holley Street Avenger on my '75.

Just so we are clear here. Even GM ran Holley's as a stock carb for many earlier vettes. They are one of the easiest carbs to setup and run. Sure some tuning may be necessary out-of-the-box, but they work well.

 

[Buckskin7T7V]

The Holley sucks up gas and has a sluggish throttle response compared to a Edelbrock. Holley also put all of their 650 carb re-build kits into one package and you have to buy all of them to get the one for your carb. There is no tech support to speak of. I replaced my 650 Holley with a 795 Q-Jet from Edlebrock and I get better mileage and performance. This is on a L-48 [77] 4-speed.

 

[69_Dream]

I'm running a 750 CFM double pumper and I couldn't be happier. Sure, it sucks a lot of fuel (maybe too much) but the performance can't be beat.

A properly tuned Holley is a thing of beauty

If gas mileage is your concern, a QJet might be for you... but I doubt most of us have corvettes to save a few bucks on gas.

Sly

 

[Vettehead Mikey]

The stock Q-jet you already have is probably the best carb for your application.

 

[KenSny]

For a street driven car, especially if it's close to stock you should not go larger than a Holley 650 and get it with vacuum secondaries. You will never go back to a Qjet if it is set up correct.

Most people that complain about Holley's install one that is WAY too big and then the car just bogs down. Just because a Qjet is a 795 doesn't mean that a 795 Holley will work on your car. Mechanical secondaries are OK IF you want to race a lot and get your foot in it fast. Get one with an electric choke.

Gas mileage? Geez, who modifies their engines with fuel economy in mind? If I want the best fuel economy I wouldn't be running a V8 that basically hasn't changed alot since '55.

Let's not start the ole Qjet/Holley debate again. They both have their place and they both can be setup to run very good.

 

[Hib Halverson]

The best choice for your car with the modifications as listed is your existing Quadrajet carburetor with, perhaps, some calibration changes.

There will be no gain in performance and certainly not in drivability, in using a Holley over a properly calibrated Quadrajet on an engine like the one being discussed.

This is not to say the Holley is a bad design or won't work on an engine like that but it is to say you don't need to change and may benefit, particularly in drivability, if you retain the QJ.

 

[maximus]

Thanks,guys,but I think I may have... opened a can of worms here...no..wait..awakened a sleeping giant. Sounds like good advice,I'll have to soak all this in

 

[Buckskin7T7V]

About the gas mileage issue.
You people are right, who care if I waste a few miles per gallon. Its only money. If it goes out the exhaust and into the air, what do I care? I have no children, so why should I care about pollution.
I lost my head and I what to thank you for putting it right.
As long as I get what I want, to hell with the rest of the world.
Once again, I am a self absorbed person.
Thanks.

 

[KenSny]

Hey, sorry we hurt your feelings. Mustn't take everything so serious. Geez. If you are all that concerned about pollution you would not be driving any kind of car. You would be walking or riding your bicycle everywhere. So let's drop the attitude and stick to the subject.

 

[maximus]

350 x 5300 divided by 3456 = percentage of volumetric efficiency

 

[maximus]

Right! I thought it was 65%-85% I have a new 625 or 650 cfm Holley "in the box",that I was gonna use on another engine for my now sold Camaro.Think I could use it on a presently stock '77 L-48? Or wait 'till I use the Performer intake & cam,Dynomax headers,etc??

 

[JohnZ]

350 x 5300 divided by 3456 = percentage of volumetric efficiency

Nope, that formula doesn't calculate VE, just CFM the engine is capable of pumping, assuming 100% VE. VE is dependent on MANY other design variables.

 

[TWINRAY]

All these mathmatical calculations are giving me a headache:crazy

 

[maximus]

Yah,and the question in my last post was not mentioned:eyerole

 

[maximus]

THANKS!:eek :duh :CRASH

 

[maximus]

OK,whats ZR-1's alter ego!? Do you remember the only bright yellow C3 in that parade?No,wait,I missed that one..I was in the Memorial Day parade :bar