the correct carb for 69 scout 80 345

[sua sponte]

How are you doing guys I came to a conclusion that when I step on peddle and I pick up speed and it boggs out... Its cuz too much air is entering due to carb seating wrong on spacer and gasket and I was wondering what carb would be the proper fit for the 345 engine or what kinda carb would fit.... So I could look around I just dont know what to ask for..

 

[Scoutboy74]

Let's start by properly identifying what you have on there now. If you're not sure, attach some good pics from both sides with filter removed and we'll id it for you from those. Main thing is we need to know if it's 2 or 4 barrel and if 4 barrel, which intake manifold do you have either square or spreadbore. Once all that intel (little bit of military lingo there in your honor) is known, we can make an informed recommendation.

 

[sua sponte]

These are the pics I got right now.... But its a 345 from a 73 Scout II. I currently have a rochester 4 barrel I dont know what the shape of the intake is.

 

[Scoutboy74]

A number of people swear by the q-jet on a Scout, including some if not all the ismails. I had one on my Scout initially. I was never that thrilled with it. Your's looks extremely funkalicious on the outside, including all associated hoses. It's likely ten times as craptacular on the inside, thus leading to your performance woes. That thing is in dire need of a full on rebuild to make it play nice. Despite what some will say on other forums, that carb is fairly complex and rebuilding one properly is not for the novice. So, you have a 4bbl intake. I see that there is a spacer/adapter under the carb. The q-jet is a spreadbore and I'm betting your intake is a squarebore. If your intake is indeed a squarebore as I suspect, the oe carb would have been a 390 cfm Holley 4150. This is the carb I have sitting atop my 392 and I like it pretty well. New versions of this carb can still be purchased. Purchasing the right list number carb is critical. I'll stop short of spouting out numbers as I'm not all that familiar with the correct aftermarket choices. If the intake turns out to be a spreadbore, the oe carb would have been a carter thermoquad. Those are similar in many respects to the q-jet you have now. No doubt mm will be chiming in on this with some additional observations/recommendations for you.

 

[sua sponte]

I think I got one of those laying around that I took off a 350... How did you get it to fit? Cuz when I tried putting it on it would hit the water outlet.

 

[Scoutboy74]

Exactly...the one you have has center-hung fuel floats with the bulbous front fuel bowl. That variation won't fit. Mine is a side-hung float with a smaller fuel bowl.

 

[Robert Kenney]

I've run many a q-jet with great sucess on boats and trucks. I marked up one of your pictures that will show how to get a bigger pump shot and better throttle responce...

One other area that can be causing the bog effect is the secondary air valve. It it vacuum actuated and can open to early.. There is a spring that resists the opening inorder to keep venturi velocities up. Been a long while since I have screwed with one but it will come back to me....

I would start by making sure you have enough timing in and I use 34-36 total on every sv I build and they have 9-1 compression running on regular pump gas... The timing will help the engine respond more quickley to throttle application and keep air flow up and quicker.

 

[sua sponte]

Do you know what kinda carb this is by looking at the pics? I dont have much info on it ..

 

[Scoutboy74]

It's a GM pattern rochester quadrajet likely from a chitvy engine for the side fuel inlet, roughly 750-800 cfm, with vacuum secondaries.

 

[Robert Kenney]

I agree,looks like every GM quadra-jet I ever worked with.

Also edelbrock markets this carb new along with some fuel metering parts to jet it correctly.

The bog deal is always a problem in the high altitude marine applications I build and if I recall correctly the qj was more susceptible than most. Still a fine carb..

 

[Michael Mayben]

That quadra shown in the pics is a pile dude! You are wasting time scruuin' with it as it needs a serious rebuild!

Those units have their own unique set of issues, but mainly bleeding liquid fuel from the plugged passages under the bowl assembly (similar to the thermoquad issues), fuel-soaked nitrophyl floats, and a choke pull-off that is non-func (that is the brain for those carbs).

Without a functional choke pull-off that "releases" properly at low manifold vacuum, the secondaries can't actuate properly. The pull-off has a calibrated orifice internally that controls the rate of release.

Edelbrock dropped their version of the quadra from their product offerings about five years ago, though no doubt some retailers still have 'em. The only source of a new commercial quadra now is jet but I'd never pay their kinda prices for a quadra.

Since that carb is sitting onna some kinda adapter, I really think that is a wrong thing to do on any IH motor! But it appears that intake is an very early, non-egr intake which must be a square bore flange set up for a Holley 4150. If you will post a longer shot of the entire top of the engine I can tell more.

I'm moving this thread to the "carb" sub-forum.

 

[sua sponte]

Here are some pics of the carb now it has been rebuilt recently.
When the hood goes down it goes to a high idle.

 

[Scoutboy74]

Well, the carb does look better on the outside. Who did the rebuild? Did you happen to take any pics of the intake with carb and spacer removed? If not, did you get a good look at the holes? Were they all four the same size or were the rear ones larger than the front? What is that orange shit gooped all along the base of the spacer? Not rtv is it? That dog ain't gunna hunt. That stuff needs to come off in favor of the appropriate gasket. I foresee major vacuum leaks in your future if you don't have them already. That might explain the idle increase with hood closed.

 

[sua sponte]

Yeah the leaks are everywhere im gonna take it apart I the morning and take pics of everything as well as look for a space that fits or gasket. I had some shop rebuild it for me.. But the orange shit.. Well, I was desperate!!!