Need carb... which is best?

[OneHotV6]

I need a new carb on my '70 and want to go with an Edlebrock instead of the stock Q-Jet.. I was looking at the performer intake and carb combo but will it fit under the stock hood? Also might go with the Edlebrock Q-Jet and keep the stock intake.. which is a better carb to go with?? It's small block with a stock hood.

Thanks!

 

[Tom B Hargrove]

I have a 72 with stock hood. When I rebuilt the engine I used an Edelbrock performer intake with a Edelbrock 600 carb and a Lt-1 air cleaner. It fit under my hood no problem. I later changed to a Holley 600 and it too fit with no problems. I didn't try my original air cleaner, but I believe it will fit also.

 

[Robin7TFour]

Tom B do you still have the edelbrock carb?


robin

 

[Tom B Hargrove]

Robin, sorry, but I put it on a 72 camero I'm building. If I hear of another one around here, I will let you know.
Tom

 

[Robin7TFour]

tom, thanks. i am trying to sell/trade this AED carb i have. the 850 double-pumper was on the car when i bought it. was definately overkill + . i am using a holley 600 ,but think i could do better with an edelbrock 600 (or 750)

allways willing to trade..


robin

 

[Evolution1980]

OneHotV6,

What carb you want to (or should) run depends entirely on your intended application, i.e. "Driving Habits". If you do a search in the C3 forum using the search function of the site, you can dig up some very lengthy and informative threads. I know this because I've watched 'em come and go every couple of months.

I'm a Q-Jet fan myself. The stock Q-Jet on the vette was a 750cfm which is plenty for most vettes out there. Now why, you may ask, am I a "Quadrajunk" fan when everyone else trashes them? Answer: Because I have someone that actually knows how to repair/tune them to the needed application. They aren't exactly user friendly, but in the hands of a skilled mechanic, they are still one of the best carbs around for cruising and the occasional race.
Smaller primaries for good fuel economy (but who cares?!?!?) and big ass secondaries when you need to stomp on it. And I'll tell ya what...when those secondaries open...woohoo! :L :L

 

[matchframe]

I heard that the Edelbrock carbs are the same as the old Carter carbs. That Edelbrock bought out Carter so they could build their own carbs without having to reinvent them. Is that true?

Bill

 

[AUSSIEVETTEMAN]

You won't be disappointed!

OnehotV6,

I have recently installed an Edelbrock Performer manifold and Edelbrock QJet 1903 to my 81 Coupe. I have a Mallory ignition system and MSD coil, so the computer isn't hooked up anymore.

All I can say is put the two on (manifold and carb), you will not be disappointed!!!!!
The engine just came alive after the old Holley 650 DP was removed. The previous owner installed it on there and it was, in my opinion, a big mistake. Everything just flowed and was meant to be there when we were installing it. It is an exact copy of the old computer controlled Rochester. It looks the same, but has an Edelbrock tag.
Of course, all to there own when making a decision on which carb to buy and install, both are good. I just prefer the Edelbrock and feel it is a far superior carby.
There I said it. That will probably open a can of worms for sure!

Good luck with your decision

Tony

 

[Grasshopper]

I used a holley 600 w/ an adapter plate and it does great , much better performance and easier to work with. thats on a 350ci

 

[Dep]

I heard that the Edelbrock carbs are the same as the old Carter carbs. That Edelbrock bought out Carter so they could build their own carbs without having to reinvent them. Is that true?

Bill

Edelbrock makes a Quadrajunk clone as well as copies of the Carter AFB (Aluminum Four Barrel) and AVS (Air Valve Secondary...used by Mopar on Roadrunners, etc). Very possibly they did buy the rights to them since the AFB is a good design. Not quite as user-friendly as a Holley, but very reliable.

Dep

 

[OneHotV6]

I know this thread has been dead for a while now but I've had my car in storage over the winter and just now going to get it moving again. I still need to replace the carb and am still looking into the Edelbrock combo.. (performer intake and 600 or 650cfm carb) My question now is, is this a direct bolt on application or does anything have to be modified? I want to get rid of the choke (divorced-style) and use the automatic that it comes with.. is this an easy swap or do I just take out the old one and use what the new carb comes with?

Thanks for any help!!

 

[81 Corvette]

On my 81 I went with a Road Deamon and an edelbrock rpm air gap. Edelbrock says the rpm air won't fit a corvette, but with a drop base and 2.5 filter, it fits fine. So far i'm pleased with the set up.

The install is pretty easy. 8 bolts off for the manifold and 8 on. just drain the coolant first and make sure you get a really good seal on the back of the block. (mine was leaking oil bad :lol) The one thing that might be an issue is the throttle cable hook up. ANd make sure you are careful with the gas line. Busted mine doing the swap.

 

[GTR1999]

Speed Demons are pretty good carbs, but run about $500. Holley Street Avenger 670 would work too, as will a Q-Jet.

 

[Chas]

I have performer stuff....

fits great and looks fine...stock hood on my L-48

I need a new carb on my '70 and want to go with an Edlebrock instead of the stock Q-Jet.. I was looking at the performer intake and carb combo but will it fit under the stock hood? Also might go with the Edlebrock Q-Jet and keep the stock intake.. which is a better carb to go with?? It's small block with a stock hood.

Thanks!

 

[OneHotV6]

Ok, I've been checking a few places other than Corvette catalogs that litter my room and found cheaper prices on carbs... and was wondering if the stock # is 1406 for the non EGR Edelbrock carb? Also, how is the Performer EPS manifold?

 

[AUSSIEVETTEMAN]

Your on the right track!

Stick with the Edelbrock carb and manifold as you have already decided. We have both and noticed a big difference in HP just by using the Holley as a boat anchor! Best thing for it. Holley carbs are not that crash hot.
Besides, the Holley we had on our Vette was a 650 CFM carb, so immediately you notice a difference in HP with the airflow of 795 compared to 650. Remember cold airflow + fuel = HP If you are running a smaller airflow carb, such as the one you mentioned 600 to 650 cfm, then you are restricting your engines ability to produce high HP. Don't make the mistake of thinking more fuel = more HP, you will just waste fuel. Unless the airflow is there you will be wasting your time.

This was the major contributor to why fuel injection increases HP. The airflow is around 1000 cfm, which was a big step up from 81 Vettes to 82 Vettes. Plus the injection runs more consistant.


Tony

 

[ernbuild]

I need a new carb on my '70 and want to go with an Edlebrock instead of the stock Q-Jet.. I was looking at the performer intake and carb combo but will it fit under the stock hood? Also might go with the Edlebrock Q-Jet and keep the stock intake.. which is a better carb to go with?? It's small block with a stock hood.

Thanks!

i fitted a power/plus crosswind and a 650 double pumper to my 78 and it fitted under the stock bonnet.also milled the choke[dont need it much on the gold coast of australia] ,however noway a stock air cleaner would fit. Ended up with a cheap 8inch dia x2 inch filter with a k&n top filter thus transforming the whole filter into a total filter. its now breaths very well. dont know if it will fit under your bonnet, but the whole package goes hard from idle to 6500 revs.
regards ernie.

 

[rpounds]

Good morning (or afternoon or evening) everyone.

My carburetor thoughts are probably not the most popular opinions on this board, but what the heck? I'll let you know what I think.

A lot of people are put off by the Q-jet, calling them names like Quadra-Junk, Quadra Bog, etc. However, I have run Q-jets on everything from a '67 El Camino SS 396 to my current '75 Vette, with a lot of others in between. Just last weekend, I rebuilt a Q-jet for my SO's '68 Firebird 400. Although they seem to be mystery to a lot of people, I find the older Q-jets pretty simple and straight forward. The bogging as the secondaries kick in has a very simple fix . . . a problem that many q-jets have because of maladjustment. Jetting changes for primaries and secondaries are simple. Gas mileage (as long as you stay out of the secondaries) is very good, while performance once the secondaries kick in is great - assuming proper setup.

I have never run the 'new' Edelbrock AFB style carb, although I had a pair of Carter AFBs on a 62 Chevy Impala with a 409. I have run Holley's on a couple of SBF's, including a '67 Mercury Cougar with a hot 302. I still prefer the Q-jet for street driven vehicle. Just my 2 cents for what it's worth.

Ron

 

[MrGibbly]

CFM Explored

If you are running a smaller airflow carb, such as the one you mentioned 600 to 650 cfm, then you are restricting your engines ability to produce high HP.

The appropriate flow rate for your engine depends on what else you've done to it. Volumetric Efficiency (VE) is one of the largest determinants to what CFM carb you should run. When I was trying to figure all this out I called Edelbrock and they gave me some decent formulas for figuring it all out. For example, to determine the CID of my "30 over" rebuilt engine they gave me this formula:

8 cylinders x .7854 x 4.030 bore x 4.030 bore x 3.48 stroke = 355 CID

With that number, RPM, a guess at VE of a stock engine and another constant you can determine the CFM the engine needs. For my application I used:

355 CID x 5500 RPM x 60% VE x 3456 = 339 CFM

I used 5500 rpm because that is about as high as I ever rev my TH350 equipped L48. I used a low VE of 60% because these motors have the weak "gas crunch" cams in them and fairly mild heads.

Last, Edelbrock recommends multiplying the number you get out of the above formulas by 120% for dual plane intake manifolds or 110% for single plane manifolds. That gave me a final number of 407 CFM for my nearly stock application. The Quadrajet is more than enough. Just get it rebuilt. If you get to crazy you can wind up with driveability problems at low-mid rpm.

The engine is an air pump. It doesn't matter how much you can get in if you can't get it out. The opposite is also true. For our motors the most limiting components are deep in the heart of the monster (cam).

 

[AUSSIEVETTEMAN]

We have been reading the same books by the looks of it Mr Gibbly!

Read on to page 114 about how cold/ dense air and it's flow produces maximum HP. Please do not quote only part of what I have posted. There is more to what I was trying to pass on. (I do respect your opinion and am not attacking you)

For a little light reading, try HP Books Rochester Carburetors by Doug Roe. This book also has the formula you have used to calculate the most effective carb. It also mentions the Venturi and it's vital role in airflow. Basically airflow produces HP, not 'pouring' fuel into the engine. You can get maximum airflow from the bigger carb with better Venturi and smaller jets to control maximum fuel efficiency.


Tony