I was reading an old carter tuning guide that I have and it showed pictures of an old nascar afb that was a three barrel. Said they were quite rare. Wonder if any one had modified a four barrel afb or avs to 3 barrel for fast.

It was rated over 900 cfm

interesting. i don't remember anything like that back in the day, but somebody could've got creative. got any pics?

Years ago there was a Hot Rod magazine with a yellow Mustang on the cover that was air born over a hill. I remember that car had a three barrel on it. That's the first time I'd ever heard of such a thing.

I remember Holley having a 3 bbl carb back in the 70s..

Think he is looking at the air door.

Nope,three-barrel 3636s used on the Pontiac NASCAR 421 super duty engines.

Top.

And that is a VERY rare carburetor!

Never could understand why that didn't "catch on" but instead the 4500 series came about...

Looks like it would be great for a hot 440, although all the ones I've seen (Holleys) have no choke.

Wow I have been around muscle cars since the late 60's and have never heard of the Carter 3 barrel only the Holley 3 barrel. Learn something every day. Ron

Look at the new Demon Thermo-Quad, they use a similar setup, they call the single butterfly a "goggle" valve because it's shaped like a pair of goggles

Looks like it would be cool to do an AVS for FAST. Or two AFB/ eddys for a big inch NSS. Wonder if a four barrel could modified and made to work.

I figured if anyone could make it work it would be you Bill. The originals were 1 to 1 on the linkage. Both ends opened at the same. Might be ok on a nascar but I believe progressive would be better. The avs would be easier as there would be no air valve to deal with. Keep us posted on how you are coming.

Those old LD 340 intakes and others of the time had the little notch in the divider for these carbs I think

So, is it an AVS or AFB? it looks like it uses the full circular Venturi, unlike the Holley. how does it transition from the two Venturi to the single throttle bore?

that is very very cool.

Very interesting carb. Do you have a pic of the top of the carb? Was it an AFB or an AVS? The top pic that is posted is a different carb from the bottom pic. Mounting holes are different.