Fuel System: Carter A.F.B. question !

[BalkaRoo]

My 63 GT Hawks 289 engine has been out of the car in storage for a while with the accessory parts in a box, and my original A.F.B. Carter has gone "walkies" I suspect knocked off by one of the visitors to the farm over the last three years.
Four barrel 289s aren't common over here, as most Studes are 259s , and I haven't found a "Studebaker" replacement, but last Saturday I picked up a Carter A.F.B. 3088S which doctor Google tells me is 61-63 Buick, but for engines several sizes larger than the 289. It has the "weighted "secondaries, not vacuum diaphragm. What I want to know is, would this be too big for the 289 ? The engine when finished will have 582 low compression heads (standard export truck type heads) with flat top pistons and standard cam and is not intended for high performance, and my other option is to fit one of several two-barrel manifolds and WW Stromberg's I have onto it.
What do you blokes think ?

[bensherb]

Given the Buick was 1961-1963 it would most likely be a 364 or 401 ci. The AFB came in over 500 different variations the differences being the throttle bore size and the secondary air valve counterweight weight, and of course jetting.

The Stude AFB had primary throttle plates 1.437" diameter and secondary plates 1.690" diameter.

I have and tried several AFB's from other car makers and found the ones from smaller engines worked worse than the larger engine versions on the Stude. The best working one I had was from a Pontiac 401 ci, and as it turns out it also has the same size throttle plates as the Stude version. There's not a lot that can easily be done about the weigh of the secondary air valve counter weight, if it's too heavy the secondaries will come on too slowly and if it's too light they'll come on too quickly. Without a flow bench and a lot of math the only way to know would be to drive it.

The info I have says the Stude AFB used .089" primary jets .077" secondary jets and .069-.058 metering needles. I ended up with .092 primary jets, .077 secondary jets and .065-.053 (#16-169) metering rods. I never did get the accelerator pump quite right, but it ran good.

After about 5 years with this AFB, I replaced it with Holley's version of a Carter "Thermoquad", they call it the Street Demon. After a lot of jetting changes it works very well. Both these carbs are in the 625cfm range. I also tried a 390 cfm Holley 4160 it worked great at low rpm but petered out at high rpm.

Shy of a carb with massive bores for the engine size, there's not really a thing as too big a carb. An engine will only take as much air/fuel as it needs. The problem comes when the carb bores are so big as to reduce air/fuel velocity too much or so small that it chokes air/fuel flow and doesn't supply enough for the engine to reach its potential. Remember too, a 4 barrel carb is just a 2 barrel until you open the secondaries, so somewhere around 1/2 the cfm give or take. The beauty of the AFB (or thermoquad) is the secondary air valve is only opened by air flow through the carb based on engine rpm and air requirement.

[altair]

I have an AFB from a 63 Buick 401 on my 259 and it works well. The only problem I had was one of the fuel pickup tubes was clogged and it took a long time to find it. Just another small point the parts are left and right if you disassemble it keep them separate.

[JoeHall]

Looks like the 3088S was for 401 Nailheads. If not already done, I'd refurbish it and doublecheck all settings, i.e. float level and drop. Then I'd install it as is, and see how it works. Would not bother to change any jets, springs or accelerator pump adjustment; it may surprise you as to how well it works on your Stude V8. Definitely worth a try.

[yeroldad]

I have a 625 AFB on my 289 in my '53 Commander, with a T5 and 3:31 rear end. It works great. I had to do a bit of tuning, which, after trying changing jets and rods, I ended up using the jets/rods that were in the carb originally, I put in the lightest springs from the kit I got and it works great. The secondary's open as they should and the car gets 25 MPG, so I ain't about to complain about that! I agree in that I would rebuild the carb you have, stick in on the motor, and go from there. You might not need to do a thing to it, or you might have to mess with, (tune) it some. Either way, I bet you will be happy with it. The one thing to check and fix, if it needs it, is the primary throttle shaft. I haven't seen very many that were too sloppy, but I have seen some. I swear by AFB carbs, and I wouldn't even put my hands on an Edelbrock clone. I have seen way to many that didn't work worth a s--t, some leaked right out of the box, and most all of them never did run decent.

[Bellingham Studenut]

I have an original 4bbl carb if interested.
A person near Tahoe wanted correct matching # to rebuild for his GT Hawk.
I found one, took pictures, talked to him about his car about 45 minutes and gave him a price.
He said he wanted it and needed the total with shipping to send to SI for rebuild.
Wrapped and packed with address and sent total. He said great I'll buy it and THEN I DIDN'T HEAR BACK AND EMAILED.
He said SI found a core to rebuild so didn't need the one I found and had Wrapped with labels waiting for USPS!
Then he emailed saying he wanted some wheel well moldings I had.

If any interest, I have pics of the carb and it's boxed ready to ship.

[StudeRich]

This Stude. Carter AFB (or ANY) COULD be a :

3540S For a '63 259/289
3726S For a '64 259/289

Probably NOT one of these:

3588S For a '63/'64 R2 289
3589S For a '63/'64 R1 289
3725S For a '63/'64 R2 289