1963 Carb Question

[Joel T.]

I was the guy who posted yesterday on the early vs late question... I gotta tell you all that I was really impressed by the amount of knowledge out there...

In any event, here is another issue which I am trying to sort out.

My (new) '63 (327/340) has what appears to be a stock chrome air cleaner. Problem is that the cleaner base does not sit flush on the carb throat, actually tilting to the left, so much so that the top of the cleaner rubs the underside of the hood. After inspection, I found that the choke shaft (actually the lever on the end) makes contact with the bottom of the air cleaner preventing the flush fit. My first thought is thst I have a poor quality replacement cleaner.

Next I check out the carb... It is a Carter AFB but has the code 3783S cast in the base as opposed to 3461S which the judging guide identifies. Under the code is stamped "K4" which leads me to believe that this is some sort of replacement carb, manufactured near the end of '64 (?), not a '63.

Now this car has a NOM supposedly manufactured around March/April '63.

The question is, while the 3783S is not the "right" carb, is it an acceptable replacement for the original 3461S? This would mean that my air cleaner is the problem... OR do I have the reverse problem and need to find a 3461S carb somewhere???

As always, I appreciate your collective thoughts,

Joel

[Gordon Peterson #4961]

Re: 1963 Carb Question

Hi Joel -

I'm not familiar with a 3783S (although one of our "parts guys" will likely fill us in). But I suspect this is a much later AFB. Maybe the K4 means '74, not '64. Anyway, would it be possible for you to post a picture of the top of the carb. I'll be glad to make a comparison with my 3461S.

I'd post a picture of mine, but we're about to head out for Cruizin.

Pete

[Bob R.]

Re: 1963 Carb Question

You may want to check the air cleaner and make sure it is correct for the 63. The 64 365 hp engine uses a similar looking unit however it is for a holly carb which has a different size opening.

[Duke W.]

Re: 1963 Carb Question

The 3461S was replaced by the 3721S in '64 and this evolved to the 3721SA and 3721SB. The 3721SB was available from both GM and the aftermarket as a replacement for earlier carbs for many years. For PG the numbers are 3460S then 3720S/SA/SB.

I don't know the application for your installed carb.

As far as judging is concerned, it's either original or not. If it's not deemed to be original you loose all originality and condition points. Something other than a 100 percent functionally bolt on replacement like the 3721 series may require other "modifications" to fit, which could result in more lost points.

Duke

[Clem Z.]

3783S, 1965 400 HP 409 chevy *NM*

[Clem Z.]

PS may bring money on E bay

to someone restoring a 1965 409 chevy

[Duke W.]

Re: 3783S, 1965 400 HP 409 chevy

Clem - I always thought the 409/400 AFB had larger primary throttle bores. I recall way back when that the 409/400 AFB was referred to as a "D-series" while the 327 carbs and the carbs used on the dual quad 409s with 1 9/16" primary throttle bores and 1/11/16" secondary throttle bores were called "C-series".

Also, I recall that the D-series had a larger diameter air horn.

So is my memory playing tricks on me again?

Duke

[Clem Z.]

Re: 3783S, 1965 400 HP 409 chevy

my list shows a 3783S as a 409 carb,maybe thats why the air cleaner does not fit correctly

[Gerard F.]

Probably got a goldmine

How many 65 409's are around. I guess it doesn't have a tag, but the chevy part number would be 3855381. Air horn casting 6-1593, main body casting 0-1549,
per Chevrolet by the Numbers.

Jerry Fuccillo
#42179

[Gerard F.]

Maybe not, here's one on ebay

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=33550&item=7979255214&rd=1&ssPageName=WDVW#ebayphotohosting

[Verne Frantz]

Re: PS may bring money on E bay

Clem,
There is also a market for a '62 380hp 409 and '63-'64 400hp 409, since that carb was the service replacement for those applications. Remember, there is no national judging venue for those cars where carb numbers are checked. In fact, hardly any numbers at all are checked.....
Verne

[Verne Frantz]

3783S = 5 1/8th" airhorn *NM*

[Duke W.]

Re: 3783S = 5 1/8th" airhorn

Okay, so the air horn IS bigger, being as how the air horn on my 3461S is about 4 9/16" OD.

I knew there was a reason I did not install one of those "D-serious" back when I was young and clueless and actually thought a "bigger carb" would make more power.

To Joel:

The probably reason the air cleaner does not fit square is because the base opening is to small to fit the air horn, which also means you have a big unfiltered air leak. You should obtain a functionally correct carb. An OE 3461S may be priced dearly, but any 3721 is probably cheaper and is functionally correct.

You may be in luck because the carb. you have may also be quite valuable. If you shop around the various vintage carb vendors, you can probably work out a trade of some kind.

Duke

[Gerard F.]

3721 on ebay

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=34198&item=4555173965&rd=1&ssPageName=WDVW

but doesn't look to good.

Tried a search for a 3461S but no results.

Jerry Fuccillo
#42179