4953mark

does anyone know the difference between these two carbs

thanks,

Mark

Avispa

They are completely different designs. The AFB has no gaskets below the fuel level, has air valves above the secondary Venturi, a single fuel inlet and an aluminum body. The 3310 is a basic Holley 4bbl with vacuum secondary throttles. It has two fuel inlets, is made from cast zinc, has replaceable metering plates that disassemble from the main Venturi housing and has a few gaskets below fuel level, like fuel bowl and metering block gaskets and mounting screw washers. Having gaskets below fuel level means you gotta keep an eye on the carb for fuel leaks.

A feature on the AFB I really like is vacuum operated mixture needles. These are pulled into the main jets by manifold vacuum and lean out the fuel mixture at light part throttle. None of the Holley 4150/4160 series carbs, which the 3310 is an example, has anything like that.

Hope that helps.

SI67

I don't know the differences, but what I suspect Mark was asking about was the difference between two different AFB carbs used in 1962:

3269 as used on 300 HP and 340 HP engines with manual transmissions

and

3310 as used on the 300 HP with Powerglide

I don't know the answer, but I hope I've clarified the question.

Steve

Frankie the Fink

The ST-12 does not list a 3310 AFB for '62.
The differences can be amazingly subtle.

In the Specification section of the ST-12 manual the specs for the internals of the 3269 are given; if you can find the equivalent manual for whatever the 3310 fits on you can get those specs and compare the two. It may not even be enough difference to "feel" on a small block...

tbarb

The power enrichment you are referring to is accomplished on a Holley by the main jets and power valve. The goal is to lean the main jets so the car drives good with a lean A/F mixture and the vacuum operated power valve enriches the mixture under load. Good thing with the Holley's is that some say they are easier to tune and jets/air bleeds are easier to access.

The metering rods on a AFB do the same thing and when the spring overcomes the engine vacuum the rod lifts out of the jet allowing more fuel to the nozzle. Good thing with the AFB is that you don't need to take the carburetor apart to tune the power enrichment. The venturi clusters usually need to be replaced to change IFR/air bleed.

I forgot the original question though so sorry if I got started..

W Guy

The 3310 is set to run leaner than the 3269. The primary and secondary jets are smaller and the step up rods are larger diameter at the cruise step. Also the primary air bleed circuit is .002" smaller on the 3310. Using a 3310 on a manual trans car will cause a stumble when the throttle is initially opened. Changing the parts mentioned as well as the primary venturi clusters will duplicate the 3269's performance.

Verne

Avispa

Oops! The joke's on me. I see "3310" and only one carburetor comes to mind.

4953mark

I bought a 3310 for a good price the secondaries are .063 and one primary is .101 and the other is .106. I haven't measured the rods as yet. the secondary jets don't want to come out. Any suggestions on their removal?

W Guy

Obviously some penetrating oil would be a good idea. Take a screwdriver and file the tip so it fits perfectly into the slot in the jet. Same width and no wiggle room. Nice snug fit and flat against the bottom of the slot. Then just lean on it. They should pop loose.

Verne