Buying New Carb – Edelbrock or Quadrajet?
 

My current carb is a Holly that I’ve have for about 15 to 20 years. Recently, I had a local Napa send it out to be rebuilt (not sure that I needed to).

The engine stalls at abrupt stops and turns. OK… adjust the floats….but I don’t see the Float Adjusting Nut (see pic’s).

So it’s time to replace it with a newer carb. Many people here have Quadrajets. I called Edelbrock; Tech support suggested to use their model 1806 (Thunder Series 650 cfm) ($368.00) which requires and adaptor plate ($35.00). Looks good to me, price is doable.

Does Quadrajet have any advantage over Edelbrock or vice versa?

It’s easy to find the Edelbrock (Summit Racing and Jegs) but search results are not showing much in the way of Quadrajets. Does Rochester makes Quadrajets?

Please advise.

67 GTO 400 Auto

Heres some ideas to think about, I dont have a perfect answer.
I think you need to identify the actual driveability problem before you throw away any more money on carbs. Did you have the Holley rebuilt hopeing to fix the problem? Who decided the Holley had problems? and how did they determine that?
It does sound a bit like its flooding out when you are making _abrupt_ stops and turns. Why do you do that anyway, are you autocrossing? I dont see any float screws on there either.LOL Probably have to remove the front bowl and set by hand on that model. Do you know the list number? I wonder if its a spreadbore Holley from the fuel economy days of the 70's?

When did the problem first occur? Was any work or modifications done just prior to the problem's beginning?

If you do eventually buy a carb, dont bother with that baby Edlebrock even though it would probably work ok. Get a real Quadrajet. Qjets havent been made for many years so get a remanufactured one from Cliff Ruggles. You will love the power and economy.

What intake manifold is on there, cant tell from the picture? If its a factory intake it already has a adapter for the Holley so you wouldnt need one for the Edelbrock anyway. Of course it may be a spreadbore Holley so it wouldnt need the adapter.

I think if it were my deal I would start by doing what you suggested, adjusting the float level.
You should get the Holley List# off the carb so you can look up the recommended float settings.
Presumably you paid good money to have it adjusted correctly already when it was rebuilt but there is also a chance the needle and seat is not sealing correctly and getting too much fuel in spite of a correct float setting.

Rochester were the original manufacturer of Q-jets.
Rochester Quadrajet is -THE- carburetor for street/strip useage, all others are substitutes, not nessecarily good ones.
Find a 1976-80 Pontiac Q-jet core, have it properly rebuilt/modified for your engine and leave the others behind.
IMHO....

It looks like a spreadbore to me. I think those are like 650 cfm's or close thereabouts. Holley also has those with vac secondaries as well.

Call "Carbking" and get one of his Thermoquads.

BVR421

I had this Holley rebuilt when I rebuilt the motor about a year ago. Why…no particular reason except for a fresh start along with the motor. Who…it was my decision.
What is “Autocrossing”?

Let me withdraw the word “abrupt”. This engine will stall in stop-and-go traffic. Besides, I think we desire a reliable engine even if an abrupt stop is necessary which is often in big city areas.

The number I saw on this carb is 7235. Could this be the list number?

The problem progressively got worse over this course of a few months with no apparent reason.

It’s a factory manifold and I think it’s a spread bore (see pic).

I did a search on Cliff Ruggles and found http://www.cliffsqjet.com/. I’ll check this out.

As I recall, it cost about $250.00 to this Holley rebuilt. I think I would rather spend the money for something easy to adjust rather than removing the bowel.

Dave,
Do you have a WEB site or phone for Carb King?

Jimib,

Been there and done that, do it right the first time buy a Q-Jet and be done with it...You will wonder why you waited so long to put the right carb on that engine... Q-jet will out perform and get better mpg....Good Luck with your project... Dave...1033/stock

dont use an adapter plate if avoidable, and it is.
they negatively afferct mixture distribution.
edelbrock's squarebores will bolt to a qjet manifold; they have dual mounting patterns drilled.
however, it wont work well with a factory intake; you need a plenum without the "top plate", like an edelbrock performer.

what about the fella that rebuilt your Holley? How long ago was it? Isn't he helping you?

I suppose I could take it back to the local Napa where they would send to who ever rebuilt it. But the more I research these Q-jets the more I want one.

yeah, maybe time to cut bait. but man, when you said you threw down $250 to get from working to not working, that seems maddening.

what about a possibility that your carb is okay, and something else is the problem? does it stall at the same time as the stops & turns, or is there a delay?

http://www.thecarburetorshop.com/

It's big. Some would say it's ugly. But it works well as my Holley or my Cliff Ruggles prepped Qjet. Call and talk to Jon. It is a spreadbore. $350

I spoke with Cliff Ruggles and I’m on the waiting list for a Q-Jet; about 6 to 8 months.

During our conversation it was brought to my attention that the original 67 manifold has a trough, or channel, or exhaust crossover or what ever it’s called (see intake pic above). Apparently, there is a metal shim that belongs here which I don’t have. I only have a gasket between the carb and intake. This could be the reason for the stall problem. This shim may have been misplaced during the motor rebuild.

Anyhow; PY has a metal shim (Part PYQ10G). Perhaps I may see an improvement.

Valve Covers...
 

David, are your valve covers the old Cal Custom ones? I have a pair of the old Cal Custom covers around here someplace, got to send them out and get them buffed up. Last count i have 3 pair of the old Mickey Thompson covers around here also.

jet remanufactured quadrajets
 

does anyone have any experience with these carbs. they sell at summitt for $389 with no wait. they have three different types ranging from stock to tricked out.

i have a quadrajet that's an 800 cfm but i need to replace the gaskets as they leak a little gas. other than that the carb ran fine. that was on a stock 250 horse '73 model 400 with 4X heads. i rebuilt the motor and should be running close to 500 horses. will my old carb be sufficient and if so how do i go about taking the choke mechanism that goes into the intake off. i have an ebrock perf. rpm now and i don't see any accomodations for this choke set up, besides i live in the deep south with warm climates. i don't want the choke on there anyhow.

I bought one of the Jet carbs, I think it was the stage 2. I ended sending it to Cliff to have him calibrate it. If I had to do it again, I'd get one from him, and do it right the first time.

Qjet custom built.

Carb recommendation
 

Go with one of Cliff's Quadrajets.

All the reman stuff is junk. All the Jet "stage" Q-jets are almost junk. They are genri-built units, mismatched parts, generic calibrations, etc. Edelbrocks are about as bad.

custom built Qjet all day long. A properly sized and done Holley is just as good for performance, but fuel mileage is worse.

Yes, your 67 manifold does have an exhaust crossover underneath the bowl area where the Q-Jet used to sit. Without that shim the heat from the exhaust will burn through your base gasket, at the least causing a vacuum problem. Whether this is causing your problem, who knows. But it will cause A problem. You dont need the shim. Tap and plug the two passages.

A Cliff built Q-JET OR a CARBKING built Q-jet or CK's TQ will outperform that holley in every way. And you won't believe the mpg and power increase !!

They are original Cal Customs. I found them on eBay and polished them myself with my Black and Decker bench grinder and a flex shaft grinder.
http://forums.maxperformanceinc.com/...ght=cal+custom
Read the two links in the opening post for the "rest of the story".

David, thanks for all that info, i have a pair here that need the polish deal, i have had them a good 20 years and never used them. Time to clean them up.