Quadra Jet Carb - Is a Riser Section Required?

[Jeffrey A.]

Attached are a couple of pictures of my Carb place on the intake manifold. I have a assmebly manual but for the 427 I seem that I can not find if a riser section is needed inorder to properly. See Picture two to see the close clearance. Under the 327 it show a riser under the carb base plate, but can not seem what goes under mine. One would assume so. If anyone know any advice is welcome and if any know were to get one is also appreciated. Jeff

[Greg L.]

Re: Quadra Jet Carb - Is a Riser Section Required?

Jeffrey I had the same problem on my 69 as you and in the end I found that the lower portion of the throttle lever was slightly bent. I discovered this while comparing it to an original carb so all I did was bend the lever to match the one on the other carb and that provided the required clearance. It doesn't clear by much but it does clear.

There is no spacer either....just the one gasket and one thin stainless plate as in the pic.

Hope that helps.

[Stuart F.]

Re: Quadra Jet Carb - Is a Riser Section Required?

I think you both might want to wait for some more input. The pictures in the first post show a ball end fitting for an automatic transmission linkage, and if he bends the linkage arm back to clear the bolt, he will still have a linkage interference. I don't know B.B. Quadrajet applications, but it certainly looks like you need to investigate further.

Stu Fox

[Patrick H.]

Re: Quadra Jet Carb - Is a Riser Section Required?

I don't know about anyone else, but I always use a base gasket (between intake and carb) that is about 3x as thick as what both of you show on your cars. I always get the FelPro brand, and they work well for me.

Jeff, where you ask in the second pic about a riser, the gasket thickness you show between the carb body and base gasket is perfect. See middle gasket below

Take a look at the pic below borrowed from carburetor.ca
The base gasket in the lower left is so thick it leaves a good shadow! The ones shown by Jeff and Greg are no more than thick paper.

I'd consider a thicker base gasket before worrying about anything else.

[Jeffrey A.]

Re: Quadra Jet Carb - Is a Riser Section Required?

Greg/Stuart and Pat - Thanks for the information it is extremely helpful. I am also in the meantime going to call the person I bought the carb from to questions him regarding the linkage. I do have the gaskets as you guys talked about. I also talked to Grant Wong after I made the post and he is also trying to help me as well. I will post any information I get so in the future others may gainfrom it. Thanks Jeff

[Patrick H.]

Re: Quadra Jet Carb - Is a Riser Section Required?

While I realize it's a little bit of 'apples and oranges" comparison, note below my 72 350.

The accelerator cable attaches to the top, not bottom, of the accelerator bracket. I suspect yours should be the same. As Stu notes, yours appears to have an extra attachment point at the bottom which is causing you a problem. Removing that and using a thicker gasket should eliminate your issues. * I don't think that your big block will use the lower stud that is causing your interference. I don't see the stud or it being used in pictures in the Dobbins book. *

Patrick

[Joe L.]

Re: Quadra Jet Carb - Is a Riser Section Required?

I don't know about anyone else, but I always use a base gasket (between intake and carb) that is about 3x as thick as what both of you show on your cars. I always get the FelPro brand, and they work well for me.

Jeff, where you ask in the second pic about a riser, the gasket thickness you show between the carb body and base gasket is perfect. See middle gasket below

Take a look at the pic below borrowed from carburetor.ca
The base gasket in the lower left is so thick it leaves a good shadow! The ones shown by Jeff and Greg are no more than thick paper.

I'd consider a thicker base gasket before worrying about anything else.

Patrick-----


The thick insulator-type base gasket can be used on a 1968-69 but it's not what was originally used. The original set-up was the thin, steel-core gasket with a thin stainless steel heat baffle between the gasket and the carb.

If the thick insulator-type gasket is used for a 1968-69, then a new choke rod needs to be fabricated that compensates for the increased thickness.

[Patrick H.]

Re: Quadra Jet Carb - Is a Riser Section Required?

Patrick-----


The thick insulator-type base gasket can be used on a 1968-69 but it's not what was originally used. The original set-up was the thin, steel-core gasket with a thin stainless steel heat baffle between the gasket and the carb.

If the thick insulator-type gasket is used for a 1968-69, then a new choke rod needs to be fabricated that compensates for the increased thickness.

Noted.
Apparently I, like Terry, can get in trouble if I attempt to extrapolate my knowledge to other years.

So is it just the extra stud on his bracket that is causing the problem?

[Joe L.]

Re: Quadra Jet Carb - Is a Riser Section Required?

Noted.
Apparently I, like Terry, can get in trouble if I attempt to extrapolate my knowledge to other years.

So is it just the extra stud on his bracket that is causing the problem?

Patrick-----


The stud is definitely mounted in an incorrect location. However, I think the throttle arm may be incorrect for the application, too.

[Greg L.]

Re: Quadra Jet Carb - Is a Riser Section Required?

Joe is correct in saying that the throttle arm is wrong for that application. The correct arm should look like the one on Patrick's car as well as in the pic that I posted. If you get the proper arm you will have enough clearance even with the thin gasket and thin stainless plate.

[Stuart F.]

Re: Quadra Jet Carb - Is a Riser Section Required?

It would be helpful if it can be established as to whether this car is an Automatic trans or Manual. The Auto Trans units, of course, will have a lower connection (be it ball end stud or hole for a rod or swival). Some early model 4-barrels did not even have the lower part on the throttle lever for the auto trans, unless it did indeed have an auto trans (and a different carb model number). Later years, say about 64 and on, had the lever for either, but only added the stud or swival for the linkage to the transmission (we called it "kick down" and I believe the factory called it TVS) if it was to be used. The carb model would still be different, but that would be for other differences, such as internal jetting.

Stu Fox

[Clem Z.]

Re: Quadra Jet Carb - Is a Riser Section Required?

It would be helpful if it can be established as to whether this car is an Automatic trans or Manual. The Auto Trans units, of course, will have a lower connection (be it ball end stud or hole for a rod or swival). Some early model 4-barrels did not even have the lower part on the throttle lever for the auto trans, unless it did indeed have an auto trans (and a different carb model number). Later years, say about 64 and on, had the lever for either, but only added the stud or swival for the linkage to the transmission (we called it "kick down" and I believe the factory called it TVS) if it was to be used. The carb model would still be different, but that would be for other differences, such as internal jetting.

Stu Fox

not BB corvette as they would have a THM 400 transmission which uses a electric kick down systerm not a cable

[Stuart F.]

Re: Quadra Jet Carb - Is a Riser Section Required?

Thanks Clem. I stand corrected.

Stu Fox

[Clem Z.]

Re: Quadra Jet Carb - Is a Riser Section Required?

Thanks Clem. I stand corrected.

Stu Fox

that is why that carb base will not work on a BB corvette