63 SWC-340HP Manifold 3794129

[Dennis B.]

This manifold normally took an AFB carb. I prefer a Holley Carb with an electric choke. Is anyone running that combination? If so can you give me the Holley number?
So far any Holley we have tried, the butterflies are hitting the manifold, and I prefer not to use a spacer if I do not have too.

Thanks in advance for any help.

[Terry D.]

Re: 63 SWC-340HP Manifold 3794129

Dennis
Why not right to the source www.holly.com and ask them. I think you will have to use a spacer or hog out the manifold but I could be wrong.
Terry

[Dennis B.]

Re: 63 SWC-340HP Manifold 3794129

Dennis
Why not right to the source www.holly.com and ask them. I think you will have to use a spacer or hog out the manifold but I could be wrong.
Terry

I did have a talk to Holley themselves and when I told them that the butterflies were too large for the intake manifold they told me the next size down was a 650CFM double pumper but could not tell me whether that one fit the GM intake either. Soon we were talking about a 570CFM that he was "pretty sure would work" That sounds like fuel starvation before I even start
I am contemplating a spacer on a 650CFM dual feed, double pump with electric choke and mechanical secondaries..... not sure whether vacuum secondaries would be better or not?

What I do not know is how much space is between the hood of a 63 and the air cleaner? Could I put a 1 inch spacer in and have the space?
The 327 is not in the car, and has not been since I bought it, so I am unsure as to how much room I have.

Perhaps those with the AFB 3461S can alleviate some stress here? I have not played with AFB since this car was new and I remember even then, that Holley was the easiest best and most stable. But, in saying that, I am unsure how " difficult, and unstable the AFB was back then. Are they a pain in the butt?

[William C.]

Re: 63 SWC-340HP Manifold 3794129

Many would say a properly setup AFB is more dependable than a Holley, but I won't go there...In general. hood clearance on a '63-67 is very close, One unspoken part of your question is could I use an aircleaner? That may be defined by what aircleaner you are referring to? One thought since you are not looking at an original configuration, why not use a '64-65 Holley manifold, which will fit a medium sized Holley (600 cfm in the original application) without the need for much worry.

[Dennis B.]

Re: 63 SWC-340HP Manifold 3794129

Many would say a properly setup AFB is more dependable than a Holley, but I won't go there...In general. hood clearance on a '63-67 is very close, One unspoken part of your question is could I use an aircleaner? That may be defined by what aircleaner you are referring to? One thought since you are not looking at an original configuration, why not use a '64-65 Holley manifold, which will fit a medium sized Holley (600 cfm in the original application) without the need for much worry.

I was trying to stay as close as possible to stock, so wanted to use the stock manifold.
If I were to buy a new manifold to fit a holley, I would likely buy the Edelbrock 4703, which has the old oil filler tube and gives the impression of the old design manifolds.

If I were to buy a 3461S AFB to fit the existing manifold, then I have an issue with the heat riser, to the choke, because I have headers with no manifold connection. So not sure how to incorporate a 3461S without changing something else out. Its a catch 22. I suppose I could weld a connection on the header but I am getting into the things I wanted to avoid?

[William C.]

Re: 63 SWC-340HP Manifold 3794129

What you have is a "catch 22" something like being a "little bit pregnant"...most headers thru mufflers aren't much more efficient than the stock 2 1/2 inch rams horn exhaust setup, and they certainly would look a lot more "stock" than a Holley on a '63 especially if you try to use an adapter to mate the holley to the stock intake.

[Dennis B.]

Re: 63 SWC-340HP Manifold 3794129

What you have is a "catch 22" something like being a "little bit pregnant"...most headers thru mufflers aren't much more efficient than the stock 2 1/2 inch rams horn exhaust setup, and they certainly would look a lot more "stock" than a Holley on a '63 especially if you try to use an adapter to mate the holley to the stock intake.

agreed So now I am putting the exhaust manifolds on the car to replace the headman headers that are on the car, so I can fit an AFB that is the only thing that fits the Intake ...which started the problem

[John H.]

Re: 63 SWC-340HP Manifold 3794129

Dennis -

No Holley is going to fit that manifold without major modifications - you have three options:

1. Use an AFB (like it came with); you'll need an electric choke kit due to your headers.

2. Use a 461 ('64-'65) or 490 ('66-'67) Corvette aluminum intake - they came with Holleys. If you use the 461 intake, you'll need an electric choke due to your headers; the 490 intake uses a 3367 or 3810 Holley with the divorced remote choke which will work with headers.

3. Use an aftermarket intake for a Holley.

[Dennis B.]

Re: 63 SWC-340HP Manifold 3794129

Dennis -

No Holley is going to fit that manifold without major modifications - you have three options:

1. Use an AFB (like it came with); you'll need an electric choke kit due to your headers.

2. Use a 461 ('64-'65) or 490 ('66-'67) Corvette aluminum intake - they came with Holleys. If you use the 461 intake, you'll need an electric choke due to your headers; the 490 intake uses a 3367 or 3810 Holley with the divorced remote choke which will work with headers.

3. Use an aftermarket intake for a Holley.

Yes I agree. I have talked to a number of Corvette people, and I think what I will do is buy and Edelbrock 2703 it has the oil filler and resembles the old manifold, then buy a Holley Ultra 4150 Avenger (650Cfm) with the valve body in Blue so it matches the car

That breaks the catch 22 and I am out of that loop , thanks everyone.

[Stuart F.]

Re: 63 SWC-340HP Manifold 3794129

If you are talking about the hot air tube for the choke, that is easily dealt with. Get yourself some aluminum tubing. Coil it around one of your header pipes, leaving about 2" of straight at the bottom and at the top. Then, use a brass coupling to connect it to another piece that goes to your choke housing. Now, aluminum dissapates heat real fast so you will need to put an insulating sleeve from the coupling to the choke housing, Also, you may find you will need to slow down the air flow to ensure it gets hot enough to operate the choke coil. To do that, set a pair of vice grips to pinch the tubing (after the coil and before the coupling) down to about 1/8" opening, pinching the tube in two places 180 degrees apart. You can also do this by trial and error, i.e. pinch once to see if that will operate the choke coil enough, add a second pinch if more heat is needed.

The above procedure was what we did back in the day with our 270 hp Vette engines with headers and dual WCFB quads.

As far as the carbs are concerned, I have played with many in my over 55 years with Chevy V8's and I grew to hate Holleys and love Carter AFB's, and Rochester 4GC's and Quadrajets. My last Holley was a spreadbore replacement for a QJ and it was a disaster - too many adjustments that made little or no difference, i.e. mechanical secondaries, double pumps, and all the bells and whistles. To me, any carb that has a gasket surface below the fuel level is a disaster waiting to happen. Then there was the fuel transfer tube on the spreadbore that would work out of it's O-Ring seal and dump gas all over the manifold!

The only thing better about a Holley are the throttle shafts which, on an older AFB, tend to wear in the aluminum base, but are easily repaired.

You talk like a 3461S AFB is an easy model to find for your 63. Not so without paying an arm and a leg for one. It is a one year only model and the best of the series for performance. It took me a number of years to find a correct replacement for my original that was stolen. Good luck with whatever you decide to do.

Stu Fox