[john65ss]

Cliff - great info. In comparing an Edelbrock 1903 and a 1910 model, I've notice that the 1910 opens a lot further. If I recall correctly, the 1903 was something like 1.39" vs 1.27 on the 1910. In fact, the 1910 that I have seems to want to open the door further than the choke-pull-off link will allow, and it tends to bind in the slot a bit at maximum opening.

[Cliff R]

The 1910 uses the wrong secondary airflap shaft, not enough room in the slot for the amount of travel. For some reason, they installed the early airflap shaft from the divorced choke carbs, not the later model shaft used on the 1975 and later carburetors with the pull-off mounted on the airhorn.

Just one of the flaws in a those carburetors, there are at least a dozen others....Cliff

[john65ss]

Originally Posted by Cliff R

The 1910 uses the wrong secondary airflap shaft, not enough room in the slot for the amount of travel. For some reason, they installed the early airflap shaft from the divorced choke carbs, not the later model shaft used on the 1975 and later carburetors with the pull-off mounted on the airhorn.

Just one of the flaws in a those carburetors, there are at least a dozen others....Cliff

That's exactly what I see on the 1910 I have - once you get the full-open position, the whole thing kind of binds up and the door doesn't open all the way cause the link / slot won't let it. I still don't understand the large holes in the secondary air valve plates that are no where close to the POE nozzles. No idea what they were trying to accomplish there?

[chipster]

Originally Posted by john65ss

I've noticed some carbs have a "duct" welded to the secondary baffle plate that shrouds the passenger side secondary discharge nozzle. What's it there for, and does it help or hurt performance (or have no effect)?

Thirty-something years ago, at what is now called the University of Northern Ohio, my carburetor teacher said that those do-hickeys where to "Compensate for deficiencies in the intake manifold." Whatever that means.
That was one of his reasons that carburetors should always be rebuilt instead of replaced whenever possible- The carburetor is matched to the engine, and nothing else will ever work as well. But then again he did get fired for being an insane alcoholic...

[FrankieT/A]

Originally Posted by john65ss

I still don't understand the large holes in the secondary air valve plates that are no where close to the POE nozzles. No idea what they were trying to accomplish there?

I believe to decrease surface area on the opposing side. Letting the low pressure under the flap to either start pulling sooner or perhaps so it could pull harder.

[67ramair4]

Thanks to SunTuned for the part! These are two pictures of the actual item that is being discussed. Pictures aren't great, but it does show the actual part.

Note: The green clip isn't part of the baffle, it held it up for the picture!