Mister

Last weekend, I bought a new carburetor base mounting gasket for my recently-rebuilt '66 Quadrajet carb.

Here's what it looks like:


The label struck me as odd. It seems to indicate that the gasket is specific not only to a small range of years, but to Oldsmobile only.

I was aware that Rochester customized Quadrajets for each individual application, but those were just changes in metering rods and jets and accelerator pumps -- all interior components. Similarly, different divisions had different choke linkages, but those too should not affect the base gasket.

So my question is this: is there actually a difference between, say, a '66 Oldsmobile 4MV and a '66 Pontiac 4MV, as far as the gasket is concerned? Or is Fel-Pro just needlessly padding their parts catalog?

Thanks for satisfying (or at least addressing) my curiosity.

mugzilla

The last two I have bought have been generic ...

I like the look of that one, the enclosed primary bore might lead to a better low end response( an olds trait) especially if matched to the manifold...

Does it match the manifold (split versus open chamber)..?

moar pics plz...

In any case my next quadrajet gaskets will be 60019s ...

Olds64

The carburetor base plate gasket is different depending on what Q-jet you have. I would ensure any replacement base plate gasket matches the one that was on your car originally.

Oldsguy

Is that for a quadrajet or for the earlier 4 jet? The holes for the primaries look awfully small. Don't exactly know when Oldsmobile switched from the 4 jet to the quadrajet.

joe_padavano

If it were a 4GC instead of a Qjet, all four holes would be about the same size. More importantly, the 4GC was replaced by the Qjet in 1966. There are differences in the Qjet base gaskets, however, particularly in the later years when there are vacuum passages in the throttle body that require sealing. Also, I like to use the thicker base gasket for a little more heat isolation.

Oldsguy

Thanks Joe, that is what I was thinking of the 4GC and now I recall that the primaries and secondaries are the same size.

Mister

I only took the one photo, but there is another picture of the whole gasket on NAPA's online catalog here

The gasket was about $10, as I recall.

Mister

There are a few details which I did not disclose in my original post. When I bought the car in 2006, I checked all the easily-visible casting numbers under the hood, and was pleased to find that all the numbers were correct for a 1966 Starfire. Except for one part -- the carburetor. The carb was a Quadrajet, but it was not original, and not even an Olds part.

After several years of patient eBay scrounging, I found the correct carb (number 7026250) and had it rebuilt. That carb is currently in a box in my trunk. So although I am unsure of my technical acumen in replacing a carburetor, at least I am sure that the intake manifold, carburetor and base gasket will all match up. I am at least somewhat reassured by the fact that, if the whole project really goes haywire, we can always go back to the previous working carburetor.

mugzilla

The gasket that I've been getting for '70 is a perimeter seal type, it is thick ...

mugzilla

I'd like to see your manifold ...

mugzilla

Oh yeh ...

I don't think '66 goats had spreadbores ...

joe_padavano

Was Pontiac still using the AFB in 1966? My 66 442 originally came with a Qjet.

mugzilla

Oops ...

goats had q's regular cars had afb ...

It was the 60's ...

Mister

As I mentioned, we (my Dad and I) haven't actually taken the old carb off yet, but when we do, I will try to take a few photos and post them.

I only see the family on holidays, so that will be Easter at the earliest.

OLD SKL 69

The quadrajet gaskets used did have some slight variations depending on the base plate used. (differed by years and divisions) If you have the right carb that belongs on your car, match up the gasket you pictured. It should line up. If it does not look right, take a picture of the bottom of the base plate and gasket and we'll see if we can help you further.

66400

You were right the first time, 1967 was the first year for Pontiac Qjets, 1966 was first year for Olds Qjets.

mugzilla

Yes I remember it now ...

Mister

We (mostly) completed work on this over the weekend. Mugzilla asked to see pictures, so I took photos of the carb replacement for many of the steps, as well as some closeups.

I've decided to put them in a new post. Stay tuned over the next day or so for the pics and captions. And more questions.

Short version: it's never as easy as I planned.