Author Topic: 78 W72 Quadrajet  (Read 1390 times)

BanditRich

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78 W72 Quadrajet
« on: December 29, 2017, 06:12:22 PM »
I have had my TA for 15 yrs now and all this time it has had an Edelbrock Performer carb on it. To my utter horror and sadness when I ran the # on it - 1406 - I found out it is only a 600 cfm.  :-(
The original owner had the engine rebuilt and put this in with the Performer intake and cam. I  think it was unwittingly done -  thinking this carb would be more powerful than the factory unit.
Needless to say I haven't been too happy about that.
I have just snagged the one that belongs on my TA fresh out of rebuild with Cliff Ruggle's kit with the ethanol resistant float etc.
My previous TA that I had in the early 90's - a 77 SE - had the W72 engine unchanged from new.
My memory of how everything was hooked up is pretty foggy all these years later so I dove into my mountain of old HPP mags and found a couple pics of a 78 W72 with the air cleaner off trying to refresh my memory.
I can see how the throttle cable & the kickdown cable are hooked onto the carb. There are 3 things I can't clearly see though-
1. What is the cable with the white plastic tube on the end of it that's hooked up on the outside part of the linkage right beside the throttle cable? This cable isn't on my car right now with the Performer carb. What is that & do I need it for the carb to work properly?
2. Could someone put up a pic or 2 clearly showing where both ends of throttle return spring hook up? The pics I am looking at in my old HPPs don't clearly show this.
3. I'm going to hook up the charcoal canister when the Quadrajet goes in its rightful place.
Which ports hook up to the carb, and which ones hook up to the vapor return lines? The one on the driver side & the one on the passenger side?


BLACK Y88 - W72/WS6                                     
Bird Of The Month - August 2004                          
"What's a Texas county mountie doing in Arkansas? Well let's see what he's got under the hood! Bye, bye baby!
Mass Firebirds -
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http://www.allgentransams.com/members_pages/mf/april2010.html

Aus78Formula

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Re: 78 W72 Quadrajet
« Reply #1 on: December 29, 2017, 08:29:01 PM »
Good chance that you won't see any performance increase if it was set up correctly, but that's enough of a reason not to swap it in first place.
Have you still got the clear emissions and vacuum line transfer on radiator support?

BanditRich

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Re: 78 W72 Quadrajet
« Reply #2 on: December 29, 2017, 11:13:27 PM »
Yes I do.
BLACK Y88 - W72/WS6                                     
Bird Of The Month - August 2004                          
"What's a Texas county mountie doing in Arkansas? Well let's see what he's got under the hood! Bye, bye baby!
Mass Firebirds -
https://www.facebook.com/groups/906060559415396/
http://www.allgentransams.com/members_pages/mf/april2010.html

aussieta

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Re: 78 W72 Quadrajet
« Reply #3 on: December 30, 2017, 03:27:40 PM »
1978 Y84 W72 WS6

BanditRich

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Re: 78 W72 Quadrajet
« Reply #4 on: December 30, 2017, 08:18:56 PM »
Thank you!  :D
BLACK Y88 - W72/WS6                                     
Bird Of The Month - August 2004                          
"What's a Texas county mountie doing in Arkansas? Well let's see what he's got under the hood! Bye, bye baby!
Mass Firebirds -
https://www.facebook.com/groups/906060559415396/
http://www.allgentransams.com/members_pages/mf/april2010.html

Re: 78 W72 Quadrajet
« Reply #4 on: December 30, 2017, 08:18:56 PM »

oldskool

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Re: 78 W72 Quadrajet
« Reply #5 on: March 01, 2018, 06:30:32 AM »
".... What is the cable with the white plastic tube on the end of it that's hooked up on the outside part of the linkage right beside the throttle cable? This cable isn't on my car right now with the Performer carb. What is that & do I need it for the carb to work properly?..."


Cruise control. And it is not needed for the carb to work properly.

These links show pics that may help you.

https://goo.gl/images/XEHy68

https://goo.gl/images/rRsQVp

https://goo.gl/images/aXy6X1

This one clearly shows the hole in the throttle lever for the cruise cable hook up. Obviously, on cars without cruise, this hole was not used.

https://goo.gl/images/1RAEhU
« Last Edit: March 01, 2018, 07:19:31 AM by oldskool »

BanditRich

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Re: 78 W72 Quadrajet
« Reply #6 on: May 12, 2018, 06:09:11 AM »
Well the quadrajet is now on my car. Got it buttoned up pumped it a few times and she fired right up. It needs a little fine tuning but even though it is a little off it already sounds a whole lot better and way meaner now that it can breathe as deep as it should be.
The original owner had tossed the factory throttle / kickdown bracket and fabricated one to work with the Edelbrock carb that still wasn't right - the throttle cable was 1" too close on this bracket so a bolt & nut was put in the slot on the throttle cable that mounts on the carb linkage. It looks like crap but I've put up with it all these yrs i've had the car because it was mostly hidden under the air intake elbow on the air cleaner.
I ordered the correct bracket from Ames Performance and it came in yesterday. Now I know why the original one was tossed - there is absolutely no way it can be mounted on there with the Performer intake.
This has me scratching my head because back in the mid 80s when I had my first TA - also a 78 w/ the 400 - I had the factory intake replaced with the Performer and they didn't say anything about not being able to use the factory throttle / kickdown bracket.
The carb swap was done in an hrs time on Tuesday and my car has been down since then because of this.
I started a flickr account and put up some pics that show how the throttle contol cable  is 1" too close to the carb but can't figure out how to post them up here.
Ames does have this bracket that says it is for Edelbrock manifolds but it doesn't say if it is also for the kickdown cable. Will this work for BOTH the throttle cable and kickdown bracket?
https://secure.amesperf.com/qilan/Detail_Web?part_num=FN386DB&order_number_e=NDU1MjUxMw%3D%3D%0A&web_access=Y
Here's a link to pics on facebook which shows how the throttle cable is 1" too close to the carb & the fabricated bracket the original owner put on there
https://www.facebook.com/231287377060893/photos/pcb.798948256961466/798948020294823/?type=3&theater&ifg=1
Has anyone here dealt with this; and what was the solution? I don't want to put a factory intake on and want to stick with kickdown & throttle cables that are on there. Help!
BLACK Y88 - W72/WS6                                     
Bird Of The Month - August 2004                          
"What's a Texas county mountie doing in Arkansas? Well let's see what he's got under the hood! Bye, bye baby!
Mass Firebirds -
https://www.facebook.com/groups/906060559415396/
http://www.allgentransams.com/members_pages/mf/april2010.html

oldskool

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Re: 78 W72 Quadrajet
« Reply #7 on: May 12, 2018, 08:53:19 PM »
I've read that the Performer intakes are shipped with a bracket for the factory cable hook-up bracket to bolt to. I think the #8014 is that bracket.

https://www.summitracing.com/parts/edl-8014/overview/

https://www.ebay.com/p/Accelerator-Cable-Edelbrock-8014/192239807?iid=123113473153

Here's a pic of what one guy did. In the thread he said these brackets came off a 1970 model, which had a 350 engine, 2-barrel carb, & TH350 trans.

https://goo.gl/images/tnnKCD

Some just make a bracket out of a piece of metal strap, and drill holes where needed. Some call this fabrication. On my race cars, I called it "riggin". I'd say something like: "If the factory parts won't work, just rig it". And "Whatever it takes".

Don't know if something like this might work, for the kick down bracket, or not.

https://www.ebay.com/p/Auto-Trans-Kickdown-Cable-Trans-Dapt-Performance-9757/214796286?iid=173144275894&_trkparms=aid%3D222007%26algo%3DSIM.MBE%26ao%3D2%26asc%3D50998%26meid%3D9481c987aa3846e8877cb85fd13a626f%26pid%3D100005%26rk%3D6%26rkt%3D12%26sd%3D232575195155%26itm%3D173144275894&_trksid=p2047675.c100005.m1851

https://www.ebay.com/itm/Gm-Chrome-Kick-Down-Cable-Bracket-/291747779688

Here's another high cost option. I'd probably just make one out of a piece of thin angle iron, before I'd pay that much for one.

https://www.jegs.com/i/JEGS-Performance-Products/555/15229/10002/-1

One of the brackets that bolts to the rear Q-jet bolts might work. This thread says that an Olds 307 used it. My guess is that other Q-jet equipped GM engines used the same, or a similar bracket.

https://gbodyforum.com/threads/late-70s-buick-350-throttle-cable-bracket.62368/

https://www.ebay.com/i/323231272657?chn=ps

The TCI 376700 bracket looks very similar.

https://www.jegs.com/i/TCI/890/376700/10002/-1

https://www.jegs.com/i/JEGS-Performance-Products/555/157313/10002/-1
« Last Edit: May 12, 2018, 10:56:08 PM by oldskool »

BanditRich

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Re: 78 W72 Quadrajet
« Reply #8 on: May 13, 2018, 06:49:58 AM »
I ordered the one from Ames that says it is specifically for Edelbrock  intakes. The tech service people aren't there on Saturday and of course the person i talked to couldn't tell me if this bracket accommodates both the throttle & kickdown cables.
My problem is the kickdown cable is in the right spot but the throttle cable needs to be about 1" closer to the firewall from where it is.
I'm going to be calling Ames tomorrow morning as soon as they open when the tech service guys are there so I won't get the "I don't know" response again.
The bracket they're selling is covered with several different holes for attatchment options so my best scenario would be if this bracket is only for the throttle cable I could possibly mount the fabbed bracket that's in my car now on the furthest forward hole to utilize it for the kickdown cable.
I had posted up on secondgengraveyard on facebook yesterday my situation and somebody posted up they have the quadrajet on a Performer intake like me and they used the factory bracket no problem without modifications. They posted a pic and it has me scratching my head. The one that Ames sent me that's supposed to be correct looked NOTHING like the one in the pic this person posted.
Here's the one Ames sent me that's supposed to be correct:
https://secure.amesperf.com/qilan/Detail_Web?part_num=FN385PA&order_number_e=NDU1MzA2Mw%3D%3D%0A&web_access=Y
I had seen the pic of it on Ames' website but I didn't know it looked nothing like the factory bracket because I had my previous TA back in the 90s and when I got this one 6 yrs after I sold that one it had this fabbed bracket on it.
BLACK Y88 - W72/WS6                                     
Bird Of The Month - August 2004                          
"What's a Texas county mountie doing in Arkansas? Well let's see what he's got under the hood! Bye, bye baby!
Mass Firebirds -
https://www.facebook.com/groups/906060559415396/
http://www.allgentransams.com/members_pages/mf/april2010.html

BanditRich

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Re: 78 W72 Quadrajet
« Reply #9 on: May 28, 2018, 05:22:55 AM »
Guys my bracket problem is over with. I had called Ames first thing that Monday morning and sure enough they told me it was only for the throttle bracket. I told the tech guy I talked to I would be calling back shortly whether to process my  order or cancel it.
I called my mechanic and he said he could possibly combine the Edelbrock bracket with the fabbed one that was already in my car. Even though it would be a Frankenstein creation it could be shot black to minimize its appearance and the upside would be no more horrible looking bolt & nut in the slot on the throttle cable. He also said there was a possible alternative which might not only be way cheaper but look 100% better & add a little more eye candy under the hood on my engine at the cruises & car shows - a MR. Gasket fully adjustable bracket which accommodates both the throttle & kickdown cables. So I told him to go for it and cancelled the order to Ames for the $112 Edelbrock bracket and sprung for the $20 Mr. Gasket one.
My mechanic got it and it solved the problem. And it looks great too.
I took it for a test drive and was blown away. Boy was I right about that 600 cfm Edelbrock carb leaving a lot of power on the table considering what's been done to my 400.
No hesitation, no bog; RIGHT NOW throttle response and the rush of torque is downright intoxicating. The tires break loose so easy now without even trying.  :shock:
Cliff Ruggles knows how to make Quadrajet carbs top performers. Getting this carb was worth every penny.  8)
If you have him rebuild your quadrajet I highly recommend it; and definitely go for the HP rebuild kit.
BLACK Y88 - W72/WS6                                     
Bird Of The Month - August 2004                          
"What's a Texas county mountie doing in Arkansas? Well let's see what he's got under the hood! Bye, bye baby!
Mass Firebirds -
https://www.facebook.com/groups/906060559415396/
http://www.allgentransams.com/members_pages/mf/april2010.html

Aus78Formula

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Re: 78 W72 Quadrajet
« Reply #10 on: May 28, 2018, 06:13:25 AM »
That other bracket is a copy of the 307 Olds bracket of the mid-80's, often used for overdrive swaps on early models Olds.

Re: 78 W72 Quadrajet
« Reply #10 on: May 28, 2018, 06:13:25 AM »
You can help support TAC!