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I am looking for a Carter AFB Part # 3725S for a blown 289.

I hope somebody out there has one for sale or can lead me in the right direction.

Also are there other Carter AFBs that can be used in or adapted to work in a blow through super-charger application?

Thanks a lot,


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Bernie, you would probably have better luck checking on the Stude Driver Forum Studebaker Drivers Club Forum for that info. IIRC, some have used the Edelbrock AFB clone with a few minor modifications but there are some R2 gurus on the SDC site that can provide some answers. Also, Bob Johnstone's Studebaker site has a lot of info on R2 carbs. I have a '63 R2 Hawk, but I haven't had to mess with the carb......yet...

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Bernie - Studebaker blow through carbs were constructed from either unobtainium or verypricium!!!

Others may be modified. Give me a call and I will explain.

573-392-7378 (Mon-Tues central time).


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Have a wee bit more time now for explanation.

To convert the Carter AFB for blow through use:

First one needs to do one's homework and pick one of the 505 different AFB's Carter made that has characteristics similar to one's needs. One size definately does not fit all (see last line in my signature). We have used the Pontiac 3300s and 3326s successfully on blow through Studebakers.

It is necessary to seal:

(A) both ends of both throttle shafts

(B) the pump shaft

© the idle mixture control screws

(A) sealing of the throttle shafts is accomplished by:

(1) removing both throttle shafts

(2) machining a groove around the shaft on both ends appoximately 1/4 inch inboard of where the shaft exits the throttle body

(3) milling a groove in the bottom of the throttle body on each side connecting the grooves in the throttle shafts, and exiting in the low pressure area in the secondary area just to each side of the auxiliary airvalve.

The low pressure in this area is sufficient to effect a "vacuum seal" on the throttle shafts.

(B) sealing the pump shaft may be accomplished by:

(1) machining a plug to fit inside the airhorn in the area where the pump shaft exits the airhorn

(2) cutting 2 neopreme washers (Carter used teflon, but I prefer neopreme for longer service) with a center hole 0.001 SMALLER than the pump shaft.

(3) acquiring a spring such as used on the idle mixture screws, but sufficiently large in diameter to slip over the pump shaft

(4) assemble in order (a) neopreme washer, (B) spring, © neopreme washer, and (d) plug and insert into the lower side of the airhorn

(5) peen the airhorn around the plug to keep it in place.

We found this procedure easier if we inserted the pump with all of the above components on the pump shaft.

© the idle mixture control screws may be sealed by:

(1) removing the screws

(2) milling a small hole in the throttle body centered on each threaded idle mixture screw hole

(3) acquire 2 neopreme washers or O-rings (I used the same neopreme washers used for the choke housing seal)

(4) acquire 2 small steel washers that will just slip over the idle mixture control screws

(5) place on each screw in order (1) the retaining spring, (B) the steel washer, and © the neopreme washer and insert into the throttle body


It may be necessary to modify the carburetor floats (don't try the foam floats, and don't ask how I know!). Carter modified the floats by inserting baffles of expanded aluminum inside the floats prior to the solders of the two halves. This is a pain. We haven't had a problem with stock floats up to around 7 psi of boost.

EDIT because I forgot: Carter also doubled the throttle body to airhorn gasket and used a rubberized material (we use Armstrong N-8090 for this gasket).


Edited by carbking (see edit history)
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