Can anyone tell me what size (cfm) the stock carburetor in an 85 camaro berlinetta is? (5.0)

thanks!

 

I believe 750 but hopefully someone else will chime in...my source was from another message board..

 

Im pretty Sure the Q-Jets on all the 3rd gens were capable of 750 cfm

 

Yes, Garage and Darth are correct.. that Q-Jet would be a 750.. I believe that is the size caburetor that was used on ALL Chevy V8's. And.. I was also told that by fooling around with the computer.. you could get your 750 pumping out 800, maybe a lil more. I don't exactly recall how he said to do it.. but I am sure somebody here will know. My bud did it to an Olds (I believe it was).. and he said it absolutely ripped after bumping the cfm up!
Matt

 

Awesome. Thanks guys!

 

ok, no problemo man!

 

Only 595CFM. They had to be modified to flow their full potential, which is 750CFM. The secondary air valves open only about 55-60* stock.

85LG4 - Not all Chevy V8's came with 750CFM carbs. Excluding the factory offered Holley's, QJets came in 2 sizes. Most received the "750CFM' version, while a few big block and heavy duty truck applications got the larger 850CFM QJet - only difference being the primaries. Messing around with the ECM doesn't do a thing for CFM ratings, much less any substantial performance gain from a CC QJet.

 

that's great information..thanks man

 

im pretty sure it would be closer to the 595 cfm because the 305 is a smaller engine. generally i would think that the 750 would be put more towards the 350. to big and you would have problems with throttle response. i could be talking out of my *** tho so someone please correct me if im wrong.

my own question to add in this thread is:

is it worth it to replace the factory quadrajet?

how much power/throttle response is noticable if done?

if so what is the best brand (holly,edelbrock,...)?

is it better to get another quadrajet or would something like a 4150 be better?

 

Ok, sorry board.. thanx Marc for clearing that up.. (and making me look like a complete idiot.. lol)
So in order for more airflow to take place.. y0u have to tinker with the secondaries and/or primaries??

Also.. I thought 750 sounded a lil high.. but thats what a mechanic dude told me.. lol..

Hey Camaroz28.. why would it have problems w/ throttle response.. to large a carb, henceforth drawing too much fuel.. or no?

Is it worth it to replace the factory Q-Jet.. lets just ask Manny.. lol.. I'd say so! Just check this thread out, where Manny tells what his gains were w/ just a Edelbrock 600 Performer..

http://web.camaross.com/forums/showt...24#post1195024

Just read this thread where Manny tells of his Edelbrock.. and he'll tell ya all about Throttle Response, If it is worth it, etc..

I have heard some bad **** about Holley.. at least regarding street applications, as they need constant tuning. BUT.. for Track or Nascar, etc.. they are supposed to be pretty damned good!
Matt

 

I would go with the Edelbrock. with the Edelbrock you don't have gaskets below the fuel and I've heard horror stories about back fires taking out the Holley carbs. I'll eventually remember what part. There's a reason that they are called Quadra-junk. It's a good carb if you can keep it tuned and figure it out. That and the Edelbrocks just look pretty!

 

Didn't mean to make anyone look bad... Just wanted to clear a few misconceptions up.

NEVER touch the primary side of a CC QJet - EVER. It will never run right, and there is virtually no performance gain there. Focus all efforts on the secondaries. Go over to www.thirdgen.org and read the tech article on the QJet - very good info in there. A set of DR secondary rods and a quick air valve spring adjustment will have your "Quadra Junk" or "Quadra Bog" running like FI. It works great for me. All you need to do to get the full airflow potential from the carb is to push open the secondary air valve butterflies open by hand (engine off ). On the passenger side just under the air horn you will see a little stop on the air valve shaft. Grind that down until the air valve doors open just past 85* Set the air valve spring tension (as described in tech article) and throw on a set of DR rods. You'll be amazed at the difference.

The full 750CFM potential of the QJet is fine for even a weak 305. Because it's a QJet, you can never go too big as long as the primaries are tuned for the engine. It will only use as much as it needs.

 

Well, Marc.. thanx for clearing those misconceptions up..
Is it ok to touch the Primaries on any other Carb, or no?
I am only 16.. so I only understand portions of what you were describing.. lol..
What do ya mean "because it is a Q-Jet you can never go too big"..? They are decen carbs if they are tuned properly?
Matt

 

Other carbs, yes. Even non computer controlled Quadrajets. Just don't touch them on the computer controlled Quadrajet.

Because of the design of the QJet, you don't match the CFM to your engine like Holley DP for example. Because of the tiny primaries and vacuum secondaries on the QJet it will only flow what the engine needs - kind of a smart carb.

QJets can run extremely well when tuned right. They do have racing classes - Super Stock, Top Stock, and a few others that require the use of a QJet. Those cars run well into the 9s on 850CFM's! QJets are complex carbs, and most don't understand how to tune them. Approach it like a Holley and you'll never get it. When tuned right they will provide power just like a Holley, but with better throttle response and much better gas mileage. It took me a while with some help of other board members but I've got mine running great.

 

9-seconds on a f'in Q-Jet 850? Wow.. not TOO shabby.. lol..
Do you actualy get more hp or lb/ft by tweakn w/ the stock Q?
Matt