[Kenth]

I have found the original 3310-1 is a 780 cfm 4150 with front and rear metering block for regular jets.
The later aftermarket 3310-2 and on is a 750 cfm 4160 with inside bowl metering plate.
All 3310´s have venturi vacuum operated secondary throttle blades.

[Cliff R]

If you can remove and replace a toilette seat you can rebuild the 3310.

The only real difficult part is installing a new diaphragm for the secondaries. Make sure to carefully align the holes in the four corners so you don't catch them with the screws and twist/tear the material and/or get a vacuum leak.

Removing old gaskets can be a real PITA depending on what was used for the last rebuild and how long it's been in service. They can be cemented to the surfaces and take a LOT of time to effectively remove all the material without damaging the coating on the metering blocks and casting.

As Tom mentioned this new fuel can be extremely hard on the castings. I've had a few of the "new" Street Avenger series in here with noticeable pitting/delaminating from the ethanol in the fuel. Most of the older designs (which I prefer to newer models) have been fine.

I work on OEM Holley carbs but only because I have long time customers with warehouses full of cars that will ask me to do a few here and there. Otherwise I stick pretty much to Q-jets with an occasional Tri-Power, 2GC, 4GC, or tractor carb brought up here that no one locally can figure out.........Cliff

PS: anyone know what the Q-jet in the last pic is off of?

[Kenth]

1970-71 Ford Fairlane / Mercury Montego 429 Cobra-Jet, missing the airvalve lockout lever?

[Tom Vaught]

The Holley 3310 carbs spec sheets say right on them the cfm can be between 750 and 780 cfm on the carbs. Most of this is based on the booster design as all of the carbs have the same venturi size and the same 1-11/16" Throttle Blades.

Can't disagree with Kenth on the advertising but the carbs can be anywhere in that 750-780 cfm range if tested they were tested on the Holley Flow stands with Fuel flowing thru them. They will flow at least 750 cfm.
The Fuel was Stoddards Solvent which has about the same Specific Gravity as Gasoline but is much safer to use in testing the carbs.

Tom V.

[NeighborsComplaint]

Originally Posted by Cliff R

PS: anyone know what the Q-jet in the last pic is off of?

429 CobraJet

[NeighborsComplaint]

I'm no Ford carburetor expert but I believe what you have is an aftermarket 780 CFM 3310 Holley that had a "pass through" front bowl installed and an owner-made transfer tube to give the appearance of an OEM Holley from Ford. All the OEM carbs were stamped with both a Ford part number and a Holley list no. and none were a List 3310 series which was strictly a Holley aftermarket part number. Note none of the fuel balance tubes on the OEM carbs were straight like yours.

Typical stampings:

DOZ 9510 AA
List 4513
(For 1970 428 CJ/SCJ 4 Speed)


DOZ 9510 AB
List 4514
(For 1970 428 CJ/SCJ Auto)


C60F-9510 M
List 3530
(600CFM for 390 GT)

[Formulajones]

Originally Posted by NeighborsComplaint

I'm no Ford carburetor expert but I believe what you have is an aftermarket 780 CFM 3310 Holley that had a "pass through" front bowl installed and an owner-made transfer tube to give the appearance of an OEM Holley from Ford. All the OEM carbs were stamped with both a Ford part number and a Holley list no. and none were a List 3310 series which was strictly a Holley aftermarket part number. Note none of the fuel balance tubes on the OEM carbs were straight like yours.

Typical stampings:

DOZ 9510 AA
List 4513
(For 1970 428 CJ/SCJ 4 Speed)


DOZ 9510 AB
List 4514
(For 1970 428 CJ/SCJ Auto)


C60F-9510 M
List 3530
(600CFM for 390 GT)

Same as the picture I provided in the early posting.

[Formulajones]

So I guess you've found out by now, you don't have a real Ford carb there.
It appears to be something made up to look like a Ford carb for what ever reason. It's a good foundation to start with and make it what ever you want.

[NeighborsComplaint]

Originally Posted by Formulajones

Same as the picture I provided in the early posting.

Yes, except the 735's are from '70 SCJ's and the 600 from a '68 390 GT

[Formulajones]

Originally Posted by NeighborsComplaint

Yes, except the 735's are from '70 SCJ's and the 600 from a '68 390 GT

The picture I provided is the original dated carb from my 69 SCJ and is in fact a 735 cfm unit. I posted that to provide something for the OP to compare to, just to see if we were even on the same page with the Ford carb he described.

As it turns out, he has a very common 3310 unit with what appears to be a Ford front bowl added to it so the fuel inlets could be changed around to mimic a Ford carb.

[Chris65LeMans]

I guess I was right that the carb came off a Ford - it’s hard to believe that someone made a fake Ford carb not to put on a Ford. That it’s not originally a Ford piece doesn’t really matter to me.

This twist kind of makes sense. My car underwent a long, multi-owner restoration before I bought it. The seller was a “mini Jay Leno” in that he rented a hangar at an airport, filled it with cars, and had his own mechanic that worked on cars in his front yard on his days off. (I did a complete restoration shortly after I bought it.)

The seller focused on Mopars and Porsches - he was tinkering with a 60’s Ferrari in his garage when I pulled up to buy my LeMans. (I think he later sold the Ferrari for $750,000.). So - he probably wasn’t a Pontiac expert, and my car certainly wasn’t “his baby,” so all he knew about it was what he was told.

All great info in this thread. My total knowledge about carburetors 3 days ago was how to adjust the mixture screws and set the idle. That info about a swapped out front bowl is a good bit of info.

Question- I see that the Ford carbs seem to have mixture screws in the secondary metering block. What does it mean if mine is there, but doesn’t have adjustment screws?

[Formulajones]

It's just the provisions are there but the circuits aren't completed.

You could add 4 corner if you desired but it requires block, main body and base plate modifications that are pretty in depth to try to explain here.

For what you're doing it's not necessary.

[Tom Vaught]

Holley did not have 4 corner idle carbs until the 4779-6 series carbs which was years after the typical Cobra Jet and Super Cobra Jet Holleys were installed.

The 1969 Ford Dominator Fuel Bowls (with the Dual Inlet Capability (fuel inlet on either side) was based off of that "Dual Inlet" Ford front bowl design. The Dominator Carbs were first created for the Ford Race Teams.

Tom V.

[Chris65LeMans]

Originally Posted by Formulajones

It's just the provisions are there but the circuits aren't completed.

You could add 4 corner if you desired but it requires block, main body and base plate modifications that are pretty in depth to try to explain here.

For what you're doing it's not necessary.

Since it runs good, I’m just Re-assembling it as it is, but I am interested in understanding: is there any functional difference between my metering block and a metering plate, or is this just a “cosmetic” modification?

[Tom Vaught]

Function wise, the Emulsion circuits on a metering block are more precise vs the metering plate slots. The "jet" holes are fixed on the metering plates and obviously you can change the jets on the Holley Metering Blocks.

At one time, Marvin B. at Quick Fuel (before he sold the company to Holley) offered a metering plate with the ability to install normal jets for metering.

Tom V.

[77 TRASHCAN]

Originally Posted by Chris65LeMans

Since it runs good, I’m just Re-assembling it as it is, but I am interested in understanding: is there any functional difference between my metering block and a metering plate, or is this just a “cosmetic” modification?

The secondary metering block allows easier secondary jet changes

[Tom Vaught]

But to install a secondary metering block, you need longer bowl screws, screw gaskets, bowl gaskets and a new metering block gasket, and a different fuel line designed for a dual metering block carb.

Tom V.

[NeighborsComplaint]

Originally Posted by Formulajones

The picture I provided is the original dated carb from my 69 SCJ and is in fact a 735 cfm unit. I posted that to provide something for the OP to compare to, just to see if we were even on the same page with the Ford carb he described.

As it turns out, he has a very common 3310 unit with what appears to be a Ford front bowl added to it so the fuel inlets could be changed around to mimic a Ford carb.

The purpose of my post was to show in detail the fuel transfer line configs on the OEM carbs and I already stated the obvious that the O/P's carb is not an OEM so get over it already.

[Cliff R]

"1970-71 Ford Fairlane / Mercury Montego 429 Cobra-Jet, missing the airvalve lockout lever?"

Correct. They are pretty rare units and a true factory "high performance" unit right off the bench.

Kind of interesting but only recently a STRONG interest in them, more so in 6 months than in the last 30 years.......I guess it just took the Ford boys a little longer to figure out that those carburetors, when correctly rebuilt and set-up are flawless on the big 429 engines.......

[tom s]

For sure the throttle arm is diff from any original Ford Holley I have owned.Tom