[racerboy]

I set idle at 6 degrees BTDC. It idled fine there. I took it out for another drive and this time the choke rod came loose (I must’ve knocked that tiny little clip off) and the choke rod got jammed on what I think is the fast idle cam and held it open. Idle was way too fast and it heated up again. You could also tell it was running too lean. I didn’t realize this until I got her back to the garage. I’m calling it quits fir the day.

The brown lever below was jammed by the choke rod. .




Not sure if you can see how it got twisted here.

[1969400HO]

Quadrajet Guru. Cliff Ruggles has gaskets & pieces, the alcohol durable parts too, and perhaps jets/rods, if you make adjustments in it.

https://cliffshighperformance.com

[steve25]

I can't recall due to how long this post is, but is that Carb on the motor now the same one this post started off with?

[chiphead]

Originally Posted by racerboy

I will try the new points but now I have a different problem. Remember that crazy loud backfire that happened last night? It blew out the plug on the driver-side head. As the car was idling, I noticed it was so much louder than yesterday. At first I thought it blew out a muffler but when I put my hand behind the head, I could feel exhaust pumping out.



Sent from my iPhone using Tapatalk

Wow holy chit. It blew the AIR injection galley plug out of the back of the head? That is a drilled passage that intersects with drilled passages in the valve bowl of each exhaust port. It was used with optional Cali smog pump. No wonder it's loud. You'll have to replace the threaded plug. It may be that the threaded plug was missing and only the press-fit plug was installed. Enough pressure and "pop" the pressed-in plug comes out. likely why it was threaded in the first place.

I'm seeing a lot of shotgunning parts here. You need to sort the ignition and then carb. Going back and forth will drive you nuts.

[steve25]

Yup!
When enough unburned fuel collects somewhere and then gets hot enough to light off it’s a big explosion!

Years ago when a plug wire came off on me at 2500 rpm I had so much fuel collect in a muffler before I could pull off the highway that when it lite off the whole body of the muffler blew off!
And these where 3 month old mufflers , not well on the way to being rusted out garbage!

[racerboy]

Hi everyone, I'm reviving this thread because I talked to Cliff R. about where to send the carb I took off of the engine (with the bad fuel inlet cement) and as I was preparing to put it in a box to ship it out, I noticed a couple of things that I wanted to get some feedback one.
First, I noticed that the little round tag on the carb has the numbers 7027273. When I bought this carb (several years back) I was told it was the correct carb for a 1967 GTO 400 HO with a manual transmission. I did a quick carb number lookup and it says that this carb is actually for a 1967 Firebird. I just wanted to know exactly what I was dealing with here.

I also noted that the aging/discoloration on the carb body and the airhorn appears to be a bit different. Is it possible that this carb is just a collection of parts that was put together to sell? Ugh. I also attached a photo of the top and bottom, figuring the experts here could help tell me what i have. I'm just trying to decide whether I should invest in a good rebuild on an 'incorrect' carb.

Thanks!

[25stevem]

If the throttle plate is a original from a F body then it will have a tab that limits the secondary to opening only 75%.

[Kenth]

Need som numbers to positively ID your Qjet.

[Kenth]

Originally Posted by 25stevem

If the throttle plate is a original from a F body then it will have a tab that limits the secondary to opening only 75%.

Do you have a picture of this "tab"?

[25stevem]

No, do you?
This is how I have heard that the Hp Rating on these F body motors was restricted.

If I am wrong then please post up what is correct.

[Kenth]

Sure, but when you said it will have a tab i assumed you could back up your statement with some facts.

I have found that 1967 and 1969 Quadrajets for 400 and 428 uses the same throttle body assembly regardless GTO or Firebird 400 or 428.

In 1968 however there is 15 different Quadrajet applications and everyone has a dedicated throttle body, so for 1968 Firebird there is plausible they used a special bent tab like this: (Thanks Rocky Rotella for the picture).

[Formulabruce]

IMHO this carb is a AC Delco Rebuild. We got these at the dealer for warranty work as they were specific to application.
Ac Delco remans at auto parts stores ( Ac Delco authorized parts stores) had a WIDE list of applications, and they had their original number
but typically NOT a application specific "circle" installed.
Every Ac rebuilt unit I installed had these circle new application number installed.
This is a perfectly good vintage carb.