Was going to be a qjet rebuild, now Holley vs. Edelbrock

[JVA]

Hi guys -

I realize this post is going to be a little religious in nature, but I need some advice.

About a month ago, while I was prepping the '67 75 for spring driving I noticed the idle was very unstable. A little investigation revealed the fast idle cam was done for, mostly flopping around and generally doing very little. I had intended on just replacing it, but a little investigation revealed the carb on the car is from a 1970 Chevy truck (#7040511), so I am *far* less married to it now than I would be if it was original. I don't know much about Quadrajets, but I can only find two places that have or can reliably get a replacement fast idle cam. Both of them have two varieties, and neither can tell me which carbs each variety is for. My plastic cam is so wrecked it's impossible to visualize what it might have looked like.

Because of this confusion and the fact I've got a Chevy carb on my Cadillac (I know, it's semantics ) I'm thinking for a short-term fix I'm going to just buy a Holley or Edelbrock from Summit and source a correct q-jet at my leisure.  I've found a lot of discussion in various places about merits of the Edelbrock 1406 (600cfm) vs. 1411 (750cfm), but I can't find anybody putting a Holley 4175-series carb (specifically the 0-80555C) on a 429. It seems a good choice given that it's designed as a q-jet replacement, so I'm not sure why there's no love for it.

Anyone care to weigh in on Edelbrock vs. Holley? Or, if anyone can point me to a reliable source for a correct Quadrajet in the same ballpark (~$400) I'm all ears. I am buried in two other projects, and want the quickest solution to Properly Running Fleetwood possible.

Thanks!

Justin VanAbrahams

[cadillacmike68]

You're right, it is blasphemy to put a holley or edelbrock carb or (gasp / shudder) intake on a Cadillac. 

Be advised that a Holley or Edelbrock may not have all of the hookups particular to Cadillac.

[JVA]

If you can point me to a functional, correct Quadrajet I am *all* ears. All I have been able to find so far is junk carbs in worse shape than mine. If I want an incorrect Quadrajet I have options, but I don't see the value of an incorrect Quadrajet has over a non-Quadrajet.

The attraction of that Holley is that it's designed to be a Quadrajet replacement, so - at least in theory - it should have a reasonably correct assortment of fittings. It even offers a front-mount fuel fitting so I don't need to muck about with that.

[acarcollector]

JVA, You might want to check out the 63/64 Cadillac website that Jason Edge runs. It is a chapter of the Cadillac/Lasalle club. There is a guy on there that posted that he had some rebuilt Rochester carbs for sale about a week ago.Also, Jason has an Edelbrock on his 64. He might be able to give you some insight as far as that goes. Good luck ,Bill      W.Smith CLC #10344

[JVA]

Thanks for the tip - I sent an email!

FWIW, Jetchips (http://jetchip.com/) does not stock any carbs for Cadillacs, but will rebuild any Quadrajet to their highly regarded specs for $300. If I can even find a rebuildable core, that's an option I would definitely pursue! All the carbs I've found thus far are missing hard parts, though, and Jet cannot furnish missing parts.

[dadscad]

Check with this company, The Carburetor Shop,   http://www.thecarburetorshop.com/index.htm

Click on "Passinger Kits" and choose Cadillac, scroll down to find your year and accessories type (A/C, A.I.R.) to get the original carburetor part number. Then give him a call or send a message describing what you need, maybe he can help with the core and or parts. The Limo used this QJet carburetor, #7027233, others are listed.

HTH, David

[TJ Hopland]

Was there anything especially unique about that carb vs the later Cad Q jets?

[R Schroeder]

Here is one that might work out for you.

http://www.ebay.com/itm/68-69-70-Cadillac-472-Quadrajet-carburetor-good-used-/400423603027?pt=Vintage_Car_Truck_Parts_Accessories&hash=item5d3b1b4b53&vxp=mtr

This one might work too.
Cheap

http://www.ebay.com/itm/1974-CADILLAC-QUADRAJET-4BBL-CARBURETOR-7043230-/321080642357?pt=Motors_Car_Truck_Parts_Accessories&hash=item4ac1e5cb35&vxp=mtr

[JVA]

TJ: I have no idea! I've been told by two places (Jet, and a local shop) that Cadillacs used a different linkage than other GM brands, but nobody can tell me how they were different, or if they were always different. What I do know is that I have a 7040511 on my car now, and it seems to work just fine... so I have no idea about anything.

Roy: That ~'68 carb looks great - fair to say it'd more or less bolt up on the 429 without much issue?

I really appreciate all the help - this car is still very much over my head.

[Rob Troxel]

There are some differences even in the same year Quadrajets based on the stamping numbers that begin with 7.  I have a Q jet on my 68 Eldorado that is not original and it does not idle well.  Would love to know the 7XXXXX numeric applications for each model on the 68s and the 67s too.l.  Any ideas on where to find? 

That one on ebay looks like a good deal but once again the 7xxxxx number tells the application best.

[JVA]

According to this page:

http://www.carburetion.com/quadnumber.htm

there isn't that much tied up in the number that would tell you anything specific about the carb - just when it was made and for what brand. Best chance would be that last digit?

Interestingly, the local shop also told me that the number in general don't mean jack since Rochester themselves didn't universally follow them. Best laid schemes, and whatnot.

All this inconsistency is what's making this whole process so difficult for me. I've got a 7040511 on my car, which should be a 1970 Chevy with California emissions and a manual transmission. It hooks up fine, runs fine, and idled fine (before the cam broke!). I just don't have a handle on what might make a 1967 Cadillac Quadrajet special in the scope of all the Quadrajets ever made - or what might make a 1968 model different... maybe jets or something to fee the extra 40ci?

[Rob Troxel]

I believe you are right in that engine size would dictate jetting and overall fuel flow. (ie 750 cfm, 800 cfm)  There is also the number of Vacuum ports as needed by the particular engine it was meant for. I understand even the vacuum ports have different applications.  I do remember reading somewhere that some of these ports may not supply a constant vacuum.  Hopefully we can get more clarification.

I'll do a shout out to Hawaii Glenn  to see what he knows on this or the numbering system.

[dadscad]

RobTroxel, this link will give you the number of the carburetor that should/could be on your car. http://www.thecarburetorshop.com/Kcadillac2.htm  There were 8 different Qjets used in 68. This chart covers 57-74 appilcations. The Carburetor Shop has the best most complets Carter AFB kits I've ever purchased. I would think their other kits would be of equal quality. I think they do carburetor repair work, also.

HTH, David

[Gene Beaird]

According to the Carburetor Shop kit reference page, it looks like several models of the 67 share carburetors with the 68.  Interesing that the 472 uses the same carb as the 472.  It looks like just about any late-60's early-70's Cadillac carburetor will work.  The important parts will be a divorced choke and the passenger side inlet, as well as the throttle linkage that'll depress the downshift switch when needed. 

Do you have some pictures of the carburetor you have?  It might be just perfect for your car, more so than an Edelbrock or Holley that will definitely require a lot of modification to the fuel line, throttle linkage and air cleaner assembly to make fit.  Post up some pics, some with earlier/later year cars can compare and contrast.  I'm thinking you're good to go with rebuilding the one you have. 

[Rob Troxel]

Thanks Guys for sounding in on my questions.  I think rebuilding is the best bet too, and as near as I can tell, there don't seem to be too many differences.  I was surprised the 67s were similar to the 68s. Wonder if the jets were larger in the 68s? Any other recs or a  carb Q-jet rebuilder?

[dadscad]

Looks like the 7040511 QJet fit a 1970 350 ( California ) Chevrolet truck.    http://www.thecarburetorshop.com/TruckkitsC.htm#TkitChev

[JVA]

Yeah, that's what I came up with from several sources as well. It's actually a big part of my confusion - I'm being told that Chevy carbs won't work on a Cadillac due to linkage, but then I've got one on my car and it works fine. So... uh?

Does that mean I can *probably* just go buy any q-jet and swap my existing linkage on and call it a day? If yes, I may just fork over a few hundred bucks to Jet for one of their carbs and be *done*.

I'll post a picture of the carb this evening - it works fine (got me from Denver to Sacramento!), but the fast idle cam is beyond repair. That is sole part I need fixed right now. I think the choke has had it too, but that's rarely an issue... weather is getting warm, and the choke is hardly needed around here.

[R Schroeder]

When they talk about linkage, it is in reference to how the gas pedal linkage hooks up to the carb.
It also has a different spring return hook up.
Someone must have modified the one on your car to work. On some of the carbs the arm just unbolts,and you change it out with a Chevy carb.
If you look on Ebay , you will see the differences.
Pulled these two off of there to show you.
The part that hooks up to gas linkage can be taken off and changed out . Two screws and its off.

[JVA]

Okay, here are a some pics of the carb that are on the car. Again, the number printed on it is 7040511.





Here they are again, in super-huge size if extra detail is helpful:

http://www.sacsaabs.org/sacsaabs.org/misc/caddy_carb_front.jpg
http://www.sacsaabs.org/sacsaabs.org/misc/caddy_carb_right.jpg
http://www.sacsaabs.org/sacsaabs.org/misc/caddy_carb_left.jpg

[R Schroeder]

Looks like someone put the correct linkage on there for the Cadillac.
If this carb works good, I would try and find the bad parts you need.
I cant see the plastic part you talking about , that is worn out, but I'm sure over time you will find the part.
I would keep checking Ebay for a similar carb, or type in the carb number in Google and see if it brings up anything.
Roy