PVC hose to???? (updated carb)

[Pearly72]

PREFACE: I checked for other threads, even on google for something of this nature. I couldn't find anything this specific.

Background: Puchased this 72 C10 2wd about a month ago. Seller said the 350 engine was rebuilt and from a 72 K10, then he put in a 700R4 auto (also rebuilt). They run well.

I'm tying up loose ends, because he had it driveable, but put this project to the side. He and his wife drove it every once in a while, but the truck really sat for a 2 to 3 yr period.

Just got it back from the mechanic to have the rear end rebuilt and ended up putting an Eaton posi in with the factory 3.73 gears.

SUBJECT: I saw the PCV hose just dangling and looked at the carb to see where it was supposed to be connected. Checked the PCV and the valve is good and clicking. I looked at the carburator and saw an outlet/inlet from the E-choke that is the same diameter of the PCV hose.

Just in case, I'm attaching a link to the pic.... I hope it works.

There is also a capped vacuum line at the base of the carb.

KICKER: I checked the serial number/code on the carb. I think this Carter Quadrajet came from a 76 or 77 Cadillac!!! So, I'm stuck!!

In deducing the size of the PCV hose and the fitting on the E-choke vacuum intake, one would think that I should just plug it in there and so-be-it.

But, the paranoid person in me doesn't want to foul my truck up and started thinking that maybe this carb was rebuilt (previous owner told me) and wasn't a match to the last one.

QUESTION: Would I foul things up if I plugged the PCV hose into the E-choke inlet valve? It is creating a pretty good vacuum, but I don't know if it needs its dedicated fresh air for the coils. Would I mess up the choke function if I did plug the hose into that? Also, the smaller capped vacuum line at the carb's base doesn't produce much vacuum and is a much smaller line than the PCV hose (not that I can't change it). I just don't want to cause any long term damage or sacrifice the function of my drivetrain.

I am going to attempt to paste a pic of what I'm dealing with. E-choke vac line is labeled "A" and capped vac line is labeled "B". At the risk of sounding dumb, I'm willing to take some technical lessons from people that know more than I and learn from the best. I would APPRECIATE the advise. Thank you in advance.

[Pearly72]

https://ibb.co/kEdFjp

[geezer#99]

LOL!!
I read your post, read about this port by the choke and just before I opened your pic I thought Ha! I bet he has a hot air choke. And I was right!
You do have a hot air choke and that’s not a vacuum port for your pcv. You need to find a correct place to plug it in. Possibly on the front right or behind the carb.
You got more pics?
We’ll find a better spot for you.
Also what’s your carb number?

[Pearly72]

Originally Posted by geezer#99

LOL!!
I read your post, read about this port by the choke and just before I opened your pic I thought Ha! I bet he has a hot air choke. And I was right!
You do have a hot air choke and that’s not a vacuum port for your pcv. You need to find a correct place to plug it in. Possibly on the front right or behind the carb.
You got more pics?
We’ll find a better spot for you.
Also what’s your carb number?

You're the best... and I'm glad I didn't plug it in. The choke is working just fine, but I hope I dont have to hook it up to the exhaust. There's a power wire connected.

Anyway, the carb number is: 17056234. I took a picture, but it was a little blurry when I zoomed in. I'll double check it tonight when I get home and just write it down to confirm. I don't have any other photos, but I will take some more when I get home tonight.

Thank you again for the response, I really appreciate it.

[Pearly72]

I really need to make sure I'm finished before I click "post". Did you see the capped off vac line under the fuel inlet, Geezer? Maybe that one and I just buy a hose/adapter that'll fit?

[geezer#99]

That capped line is a manifold vacuum port. Sometimes used for vacuum to the distributor.
Too small for a pcv hose.
Take some more pics, we’ll get you figured out.

[Pearly72]

Originally Posted by geezer#99

That capped line is a manifold vacuum port. Sometimes used for vacuum to the distributor.
Too small for a pcv hose.
Take some more pics, we’ll get you figured out.

Here are the pics. First, I was able to get a clearer pic of the code: Now I believe the carb is for a 76/77 Pontiac (hopefully a cool one). Second, I just barely saw the bolt screwed in to the rear of the carb. Hmmm.

Geezer, thanks again for your help.

Pic links:

[IMG]https://ibb.co/c09ES9[IMG]
[IMG]https://ibb.co/eC6uS9[IMG]
[IMG]https://ibb.co/fyh179[IMG]
[IMG]https://ibb.co/eQXvZp[IMG]
[IMG]https://ibb.co/hxguS9[IMG]

Just in case the above attempted inserted pics don’t work:
https://ibb.co/eQXvZp
https://ibb.co/hxguS9
https://ibb.co/fyh179
https://ibb.co/eC6uS9
https://ibb.co/c09ES9

[geezer#99]

A bolt!
Yup! Strange things you see used to plug a vacuum hole.
Hopefully the threads are still good.
You can remove that bolt and put your pcv hose there.
You’ll need a fitting to hook it up.
Parts stores have them. Sometimes plumbing sections in hardware stores have them.
Look here. Top row on the right is what you need.
https://www.classicindustries.com/sh...uum%20Fittings

What’s the big yellow cap covering on the top of the carb?
And what do you have for a breather on your valve cover?

[Dead Parrot]

The bolt is in the hole normally used for the power brake vacuum.

Don't think that is a Chevy Qjet. Every Chevy Qjet I have seen has the fuel coming in from the passenger side into a casting for the fuel filter that makes the 90* bend internal. On a Chevy Qjet, the PCV goes into a 3/8 connector off the throttle plate under the fuel filter.

OTOH, every Chevy Qjet I have had has leaked at the casting plug in the fuel filter housing.

[rpmerf]

17056234

170 - 76+
56 - 1976
2 - 49 state emissions
3 - Cadillac
4 - Automatic transmission

Don't know what help this is.
http://www.corvettefaq.com/c3/QJetTuningPaper.doc
Can't see the pictures, but I am at work, so they might be blocked.

[Pearly72]

Originally Posted by geezer#99

A bolt!
Yup! Strange things you see used to plug a vacuum hole.
Hopefully the threads are still good.
You can remove that bolt and put your pcv hose there.
You’ll need a fitting to hook it up.
Parts stores have them. Sometimes plumbing sections in hardware stores have them.
Look here. Top row on the right is what you need.
https://www.classicindustries.com/sh...uum%20Fittings

What’s the big yellow cap covering on the top of the carb?
And what do you have for a breather on your valve cover?

I was afraid my hunches were right with that bolt when i was looking last night. I was thinking the same... Hopefully the threads are still good. Who does that?!?! However, when i was looking at comparable carbs of the same model, they had bolts in the back... But, this one on mine looks like a construction bolt. SMH!

Hopefully they have the fittings at a NAPA or any other store, so i can test fit first.

As far as a breather, it's on the opposite side and is a combo with the fill cap. The yellow plug appears to be some sort of cap.… or maybe a support for the air cleaner? I'll investigate further when i have some time and get to know this truck.

Geezer, i appreciate your assistance. I was hoping that with the limited time I have right now to get these odds and ends on my truck zipped up, my mechanic would work on these little things, because he's meticulous. But, he likes quick and easy jobs. Thank you for your willingness to jump on helping me out!

[Pearly72]

Originally Posted by rpmerf

17056234

170 - 76+
56 - 1976
2 - 49 state emissions
3 - Cadillac
4 - Automatic transmission

Don't know what help this is.
http://www.corvettefaq.com/c3/QJetTuningPaper.doc
Can't see the pictures, but I am at work, so they might be blocked.

After getting a better picture, the 7th number is a 6: Pontiac (maybe on a 76 or 77). I'll have to look at the ports for the bumps, but probably an 800cfm?

Thank you for the decode link.

[Pearly72]

Originally Posted by Dead Parrot

The bolt is in the hole normally used for the power brake vacuum.

Don't think that is a Chevy Qjet. Every Chevy Qjet I have seen has the fuel coming in from the passenger side into a casting for the fuel filter that makes the 90* bend internal. On a Chevy Qjet, the PCV goes into a 3/8 connector off the throttle plate under the fuel filter.

OTOH, every Chevy Qjet I have had has leaked at the casting plug in the fuel filter housing.

Do you still run a Qjet? For future reference, what's a good replacement (Fuel injection? 😂&#128514?

This bad boy is now determined to be for a 76+ Pontiac. The brake booster is plumbed to the rear of the intake manifold on mine.

[rpmerf]

So it's 17056264. Yes Pontiac, should be a 76 given the '56'. Google returns more info on that code. Looks like it is an 800 CFM.

[geezer#99]

Here’s something else you can use to replace the bolt.
Called a barbed fitting.
https://www.homedepot.com/p/Watts-5-...A493/202309789

[cadillac_al]

All Qjets have a PCV port on the front. This one is under the fuel filter. Your intake is for a divorced choke so you have no way to use the hot air choke on the carb. You will have to convert it to electric choke, or a hand choke if you are cheap like me.

[geezer#99]

Wrong Al!
His doesn’t. Look at his pics.
And he already has an electric choke. Converted hot air choke.

[Pearly72]

I'll try that barbed fitting, unless I find a car parts store that has one. Haven't found one yet. So, Home Depot will be my last resort... and will hopefully fit (size and threat type). Thank you again!

[SilverMiner]

Originally Posted by geezer#99

Wrong Al!
His doesn’t. Look at his pics.
And he already has an electric choke. Converted hot air choke.

Geezer - his photos do a poor job showing it, but I can guarantee there is a 3/8 port ideally suited for the PCV hose under the fuel inlet and offset slightly to the drivers side. The BOP/Cad style inlet does a good job of hiding it. See the attached photo with identifying arrow.

All Qjets feature this port, and it would be a significant vacuum leak if it is not plugged or hooked up to something like the PCV valve. The choke was definitely converted from hot air to electric, which is a useful upgrade.

[Dead Parrot]

Originally Posted by Pearly72

Do you still run a Qjet? For future reference, what's a good replacement (Fuel injection? 😂&#128514?

This bad boy is now determined to be for a 76+ Pontiac. The brake booster is plumbed to the rear of the intake manifold on mine.

When my last Qjet started leaking from the fuel filter plug, went to an Eddy 1405. It has worked fine for many years.

Have wondered about using a non Chevy Qjet to avoid the leak. How well does that one clear the thermostat housing?

[geezer#99]

Originally Posted by SilverMiner

Geezer - his photos do a poor job showing it, but I can guarantee there is a 3/8 port ideally suited for the PCV hose under the fuel inlet and offset slightly to the drivers side. The BOP/Cad style inlet does a good job of hiding it. See the attached photo with identifying arrow.

All Qjets feature this port, and it would be a significant vacuum leak if it is not plugged or hooked up to something like the PCV valve. The choke was definitely converted from hot air to electric, which is a useful upgrade.

I see both. His and yours. Both in the same port size. Which isn’t big enough for a 3/8 inch hose to slide onto snuggly.
Likely your normal 5/16 inch size port.

Look at this one. Big tube for pcv. Right where your little tube is.
https://www.carbjunkys.com/Buick-Qua...-p/7042243.htm

[geezer#99]

Originally Posted by Dead Parrot

When my last Qjet started leaking from the fuel filter plug, went to an Eddy 1405. It has worked fine for many years.

Have wondered about using a non Chevy Qjet to avoid the leak. How well does that one clear the thermostat housing?

Whether you have a Chevy style sideways or other style straight ahead fuel line makes no difference whether it will leak. They both have fine threads which get stripped easily from heavy handed installers. Or they leave the gasket out.
The fine threads have been the early demise for many quadrajets.
There’s a cure for it.
New self-tapping fittings.

[Dead Parrot]

Never had much problem with leakage from the threads. Mine always leaked from the press fit plug for casting/milling hole that faces forward.

[cadillac_al]

That PCV fitting does look small in the pics but I still think a 3/8" hose will fit snugly on that fitting. If it's 5/16" then so be it, find a 5/16" PCV valve.

[Pearly72]

Thanks to all again, for all of the replies and advise. Forums like these are the best invention since the C10s and an all-American cheeseburger. I ended up getting the fitting from HD that Geezer found (but 3/8") and screwed it in the rear port on that Pontiac carb and plugged in the PCV hose. That part is in business!!! It's hard taking over someone's unfinished project... I was able to hand tighten the dang valve cover bolts by hand (2 turns), before i snugged them down with the wrench🙄

Thanks again!!!