C2 340HP Manifold

[Richard S.]

Appreciate if someone would post a picture of the carburetor mounting surface when looking into the alu manifold for a stock 340HP car. Trying to see if the manifold bores may have been modified. Picture is a good starting point.

[Joe L.]

Re: C2 340HP Manifold

Appreciate if someone would post a picture of the carburetor mounting surface when looking into the alu manifold for a stock 340HP car. Trying to see if the manifold bores may have been modified. Picture is a good starting point.

Richard------


Attached is a photo of the carb mounting flange of an unmodified GM #3794129 manifold. The only non-original feature here is that the carb mounting stud holes have had thread repair inserts installed.

[Richard G.]

Re: C2 340HP Manifold

Here is another picture;

Don't forget about the differences, early and late, or the top where the round aluminum casting hump is.
It is located between the distributor hole and the carburetor.

[Richard S.]

Re: C2 340HP Manifold

Thanks Joe for the fine picture. It appears identical to the manifold I have. My manifold has a tapped hole located behind and to the rear of the carb, any idea what that was used for?
Rich

[Richard S.]

Re: C2 340HP Manifold

Thank you Rich for the manifold photo and the added configuration detail. Where did you send your manifold and what process was used to get the nice original aluminum finish on your manifold?
Rich

[Richard G.]

Re: C2 340HP Manifold

If it is the taped hole shown in the picture your are referring to a 90 degree fitting goes there and the PCV valve attaches to the fitting.


The intake went to Corvette Specialties of Oregon (Wilsonville) for the refinish.
I was very happy with the results. I believe it was wheel abraded but of course Dean didn't let on what the process was.
There is no paint or other application on the intake. The surface pores are closed up nicely and it doesn't appear to stain easily.
Rick

[Richard G.]

Re: C2 340HP Manifold

I found a picture of the PVC system. In the prior post I forgot to mention the brass threaded adapter that goes into the carburetor. It may be 1/4P to 3/8P thread.
Don't hook up the throttle control rod like the one in the picture. It's installed backwards.



Rick

[Richard S.]

Re: C2 340HP Manifold

Rich, no not the carb fitting but the taped hole in the manifold to the rear of the carb itself (about 2 inch behind the carb). The view of the manifold/carb you have attached is identical to mine.
Thanks
Rich

[Richard S.]

Re: C2 340HP Manifold

Very nice, thanks the the information on cleaning of the intake manifold.
RIch

[Chris D.]

[Richard G.]

Re: C2 340HP Manifold

The intake was manufactured with and without the pad for the vacuum port. It is my understanding the early ones didn't have the pad. I believe this pad was never drill and tapped from the factory. I failed to find any information on the pad in the judging manual. Possible someone can provide the switch over data. Mine had the untapped pad and is a December 1962 Car.
Pictures of both types of intake below;


Or am I confusing 62 intakes with the 63's?

[Richard S.]

Re: C2 340HP Manifold

Rich
Thanks for that insight. My car is also a Dec car, second week. I just took a look in my (older) judging manual and found no detail on the port. Well at least I now know it was placed for a 64 car.
Thanks again
Rich S.

[Richard S.]

Re: C2 340HP Manifold

Thanks Chris for the information. After all these years have gone by I never gave that port much consideration.
Rich S.

[Bob R.]

Re: C2 340HP Manifold

The 64 intake used a Holly carburetor and the 63 used a Carter carburetor they are not interchangeable the 64 intake will not accept a Carter carburetor.

[Richard S.]

Re: C2 340HP Manifold

Bob
That was not the question. I have a 63 340 HP car with the correct AFB (fits fine). I was trying to determine if my manifold had ever been modified. I have had the car since early 1965.
Thanks
Rich S