Author Topic: Contemplating Pontiac 7042262 Rebuild  (Read 954 times)

Offline SoonerD

  • Newbie
  • *
  • Posts: 4
Contemplating Pontiac 7042262 Rebuild
« on: April 04, 2023, 07:35:35 AM »
Newbie here and first post.  I have had a 1972 Pontiac Quadrajet #7042262 for about 24 years sitting in a box that I acquired which I have never used.  I have a ’71 Pontiac 455 out of a GTO that I plan on rebuilding someday and using it on.  I plan on using a factory Ram Air IV (041) cam with Rhoads lifters.  The block is currently a standard bore and will likely need to go at least .010” over and possibly .030” over.  I have an original Edelbrock Torker manifold that I got when I bought the motor.  At some point I will need a ’69 or ’70 GTO to put it in though and I plan on utilizing a manual transmission.    ;D

I was thinking of getting some exercise in and rebuild the carb.  I noticed that the previous owner has either removed or modified a couple of things on the carb and I want to bring it back to original condition with the following questions.

First, looking at the attached pictures, the top riser opening on the float bowl cover above the fuel inlet appears to have been cut down and doesn’t stick up as high as it should.  Is this top cover a readily available part so I can replace it?

Second, the vacuum diaphragm (pull off) is missing and the primary lever mechanism has been modified.  Maybe this was removed intentionally….who knows but it looks like it since it has a weld and appears to have had a grinder used on it.  Is it feasible to correct the lever mechanism and bring back to original?  I know I can get a replacement vacuum pull off assembly with linkage, but the lever arrangement has me concerned.

Third, the nipple where the vacuum diaphragm hose connects to on the body is missing as you can see on the picture.  Are these nipples available so I can install a new one?  Should there also be a second nipple above the hole where the vacuum nipple goes seeing as it looks like it has been plugged……not sure what this vacuum connection would be used for?
Lastly, are there any springs or anything else that appears to be missing that may be needed on the completed carb assembly?
I am not new to cars but am not too familiar with Quadrajets.  Any input is appreciated.

Offline Cliff Ruggles

  • Administrator
  • Qjet Hero
  • *****
  • Posts: 5401
Re: Contemplating Pontiac 7042262 Rebuild
« Reply #1 on: April 05, 2023, 08:12:12 AM »
It's not too bad overall.  Might want to take it apart and see what's missing or "hacked" internally.

I have plenty of 1971-72 Pontiac choke brackets here, plus the link and pull-off.  It doesn't have the correct one on it anyhow.

Those are excellent carburetors but divorced choke.  Forget the Torker intake, they are a "turd".  A factory cast iron 68-72 would be a lot better, and divorced choke to match the carburetor.

I can help out with rebuild and tuning parts, pull-off etc, have all those items in stock......

Offline SoonerD

  • Newbie
  • *
  • Posts: 4
Re: Contemplating Pontiac 7042262 Rebuild
« Reply #2 on: April 05, 2023, 10:11:02 PM »
Thanks for the feedback Cliff.  I took it apart and the choke bracket was wired on the inside to keep it in place instead of with a clip like I would expect.  It does look like I will need a new bracket assembly, link and pull-off to go along with a rebuild kit with any necessary performance upgrades.

It doesn't look like anything on the inside us "hacked" up and looks pretty good to me.  I was also able to clean out the top hole above the choke vacuum connection because it was plugged off (see pic).

Does it look like I will need a new top vent piece because it looks to be trimmed down?

Offline SoonerD

  • Newbie
  • *
  • Posts: 4
Re: Contemplating Pontiac 7042262 Rebuild
« Reply #3 on: April 06, 2023, 04:26:12 AM »
Also note that the primary metering rods are #42 and the secondary rods are #CR.  I don't see any numbers on the jets.

Offline Cliff Ruggles

  • Administrator
  • Qjet Hero
  • *****
  • Posts: 5401
Re: Contemplating Pontiac 7042262 Rebuild
« Reply #4 on: April 07, 2023, 03:07:04 AM »
The plugged off vacuum hole in the casting was used to supply manifold vacuum to the transmission vacuum modulator.  If you need that port I'd install another fitting in it, otherwise blocking it off is fine.

Good news that the carb is intact internally and not hacked up there as well.  The choke bracket will need to be replaced with the correct part.  I'm pretty sure I have some here.  Those take the wider metal choke pull-off which I prefer to the plastic one as they are much better made parts these days....