63 AFB Anomaly

[Stuart F.]

I recently refurbished/rebuilt the original (?) AFB from my 63 340HP. (My car was built July 9, 1963). Back in the early 90's I put on a new replacement carb (3721SB) due to choke issues and general grunginess of the original that wouldn't clean up with any of the usual carb cleaning solutions, and I was trying to prep the car for shows. The rehab is mostly done now and it came out looking like new, but I am still trying to get the last few parts to complete it.

1) I have learned, thanks to my learned TDB friends, that I should have a screen behind the inlet fitting (found @ Paragon).

2) Due to the cost of a new Choke cover and spring, I will box the carb w/o for now or, if I use it, may go with one of the electric units I have in my stock (as an experiment).

3) I can't find the correct red fiber gasket that goes behind the fuel inlet fitting in any catalog. It is 7/8" o.d. x 5/8" i.d. DOES ANY ONE KNOW A SOURCE FOR THIS? I can reuse the old one, but would like to find a new one.

4) I was trying to track down all the data on this carb in order to purchase a new tag for it. Since the car was new, I don't recall this carb ever having a tag. I have put a kit in it several times before and cleaned it. The car has never been out of my hands for someone else to mess with since new. In looking it over very closely last night checking for embossed numbers, etc., I found all the numbers to be correct for the top, the body, and the choke housing. But, What blew my mind is what appears to be a model number embossed on the front of the body; 3720SA WHAT?? In all my info of AFB's, this tranlates into an early 64 automatic. HOW CAN THAT BE? First of all, the throttle shafts are correct for a manual transmission (no trans kick down connection), and they have never been out or replaced. The thing never had an inlet screen, but I believe one will fit in the cavity behind the inlet fitting. This carb has the brass vent tubes, unlike my replacement 3721SB which are rolled aluminum so it appears to be of 63 vintage.

Any thoughts? I'd appreciate your input. I don't intend to put this carb back on as I don't plan to show the car anymore, and the replacement has the best of every change in jetting and venturis in it anyway (it runs great).

Stu Fox

[Timothy B.]

Re: 63 AFB Anomaly

Stu,
The correct carburetor for your car is 3461S but I am sure you know this. My friend had a serial # 15??- 64 convertable that also had a 3461S so I know the 63 carburetor continued into early 64. If you were questoning weather the 3720 could have been installed on your car I would say no. What is the date code below the # 3720?

[Cecil L.]

Re: 63 AFB Anomaly

Stu,
I could almost see a 3720S being used on a late production 63 if the 3460/61 stock was exhausted but the fact that it doesn't have an automatic throttle shaft might seem to indicate substitution of the 3720 stamped body on an otherwise 3461 carb (or a stamping error). Maybe they ran out of stamped 3461 bodies and used the next best thing since it has the same casting number. The only big problem with this theory is that the SA designation supposedly didn't show up until November, 63. Could it have been replaced by the dealer on warranty or regular service work without your knowledge?
There was a 3270 used on the 61 409 but it was a 5.5 " carb with 1593 top and 1433 body.... Number is similar (if you're dyslexic) but very different carb.
The only other one I can think of that is close is also a 61 carb and that is a 3220 or 21 with a 1518 top and 1412 body.

[Stuart F.]

Re: 63 AFB Anomaly

Thanks for your responses Tim and Cecil. I went and checked for a date code under the model number on the front of the body. Now that all the grunge is removed I can see more evidence that something happened. The code is K4. A good part of that time between1964 and 1972 the car was in storage except for a few months late in 1963. I let my best friend in the Army use it to go to California from New Mexico to check on a job. He got out before me and I came down on levie to go to SEA. He got the job and stayed there for a couple months before he became disenchanted with the California scene and returned with the car to Wisconsin where, in November 63, we put it in storage just before I left for overseas. I returned in January 65, but we left the car in storage until spring 65. I used it then until late 1966 when it went back in storage while I returned to SEA to work on contracts until January 1972.

Now something happened during that time and I will never know what. He passed away in 1975, his Mother is gone, and I lost track of his sister. It is a real mystery and I could lose sleep over it, but what the heck. He saved the receipts for service he had done to it while he had it, which was minimal. I could check them, but even then the time line does not fit. I trusted him with my life and still would. End of story.

Thanks again for your help.

Stu Fox

[Timothy B.]

Re: 63 AFB Anomaly

Stu,
The date indicates October 64 so this is a good carburetor for someone and I bet it will make a nice trade in for the correct 3461S carburetor.

[Stuart F.]

Re: 63 AFB Anomaly

Thanks Tim for the encouraging advice to use the carb to trade for a correct one. Believe me, I was almost devastated to learn that what I always assumed was my original 3461S carb is not. I can't for the life of me figure out how that happened or when, and I know that I will never really find out so why lose sleep over it. It shouldn't mean so much, after all, it's just a carburetor. But it's like a "***** in my armor" about which I was always proud to say; "yep, that's my 63 Vette, I bought it new and had it ever since". Ironically, I had recorded the Model 3720SA number and specs on one of my 3" x 5" cards for my file, probably the first time I put a kit in it many years ago. I came across it when I began the rebuild about a month ago, but never put 2 and 2 together. I had no reason to believe that "the carb in the box" was anything but my original 3461S.

Thanks again;

Stu Fox

[Stuart F.]

Re: 63 AFB Anomaly

Sure glad this forum has a "politically correct" edit feature. The last thing I would want to do is make a remark that would slur my wife's heritage. she would get a big laugh out of it. actually, she is my greatest supporter. Over the years there were a number of times I considered selling my Vette, but she wouldn't hear of it. And yet, I can't get her to go for a ride in it and only recently (due to our ages) got her to let me put her name on the title.

Stu Fox

[Stuart F.]

Re: 63 AFB Anomaly

For what it's worth, I would like to report that I believe I have solved the mystery of how/when my original (?) carburetor got switched from the 3461S to a 3720SA. I checked through my receipts for work I had done when the car was laid up for repairs in 1992 (I had hit a deer at 35mph). The Corvette shop in Downers Grove, Illinois that did the body repairs also did a number of mechanical repairs/upgrades for me. I had them change the brake hydraulics (steel lines, fittings, hoses and wheel cylinders), remove a dent in my pan from a previous off road excursion, and a number of other items - some requested and others on "an assumed blank check basis". Included in this work was change out of the Carburetor and fuel lines to new parts that I supplied. During the course of this work, they managed to steal my original starter, windshield wiper motor, fan clutch and unique 63 master cylinder. I guess it's not to difficult to surmise that when they changed out the carb they swapped out my 3461S for another old 3720SA and returned it to me in my box without my knowing for all these years. Shame on me, and thank you again Mr. Fara.