Suggestions for carburetor for 1967 imperial

[67imperial]

Hey everyone. I have a 67 imperial and have been running a double pumper that just pours gas into the intake. Any suggestions on what carburetor i should run? Or maybe someone has one for sale i can slap on? Thank you in advance

 

[413]

Factory Carter AVS, or a new edelbrock avs

 

[CBODY67]

The stock OEM carburetor might have been a Holley 4160 vac secondary carburetor of about 600cfm. It worked good for the first few years, until the gaskets started to deteriorate. Gaskets are much better now, but Holley has flaked their current carburetor offerings quie a bit from what they were. Screw-in air bleeds and 4-corner idle circuits to make them more universal in nature. As if thier main emphasis is on their EFI systems. Parts for the older carbs are still hiding in the nooks and crannies of the Holley website, but not in plain open sight as in the past, it seems.

Many late-1960s Chrysler and Imperial owners opted to get their Holleys replaced with similar OEM Carter AFBs, which ran forever with no durability issues. In the current time, I would lean toward the AVS2 Edelbrock of about 600cfm with an electric choke. Many have commented on the better throttle response the primary side annular discharge venturis offer. That's what I'd gravitate toward, all things considered.

Double pumper? Not sure WHY people tend to gravitate toward that carburetor for a street car with a OEM cam in their OEM motor? I remember hearing of some trailer-towing owners with 454 Chevrolet tow rigs who bought them as in their application, the vac secondaries could open unexpectedly, so they needed a manual-secondary carb for better throttle control. Otherwise, no real need for such, to me.

You will need the corresponding throttle linkage adapter which Edelbrock sells to bolt to the carb's linkage hookup to adapt it to Chrysler linkages and cruise controls. Just use the existing throttle linkage stud.

Before Edelbrock came out with their AVS carburetors, the "go-to" carb was the Edelbrock AFB 600cfm electric choke carburetor. In general, though, the AVS2 offers the improved primary venturi items, as the AFBs still have the prior types of primary venturis.

Enjoy!
CBODY67

 

[Darter6]

AVS2 Edelbrock

Over the years I have installed and ran dozens myself, the AVS2 in 500,650 and the 800 sizes.
Not much tuning needed for a street driven car 99% good right out of the box.

 

[Gregg Benedict]

Before Edelbrock came out with their AVS carburetors, the "go-to" carb was the Edelbrock AFB 600cfm electric choke carburetor. In general, though, the AVS2 offers the improved primary venturi items, as the AFBs still have the prior types of primary venturis.

Enjoy!
CBODY67

Isn't the AVS2 a spreadbore carb, and the AFB the squarebore? Wouldn't you need to get some type of adapter to use the AVS on the stock '68 440 manifold?

-Gregg B.

 

[CBODY67]

No, both are "dual pattern" bases, as pre-1968 AFBs had their normal "narrow pattern" flanges, with the 1968 "Holley flange" being what the AVS carb was. Neither are "spread-bores", with 1.38" primaries and 2.25" secondaries. The Carter Thermoquad is a spreadbore, just as the Rochester Quadrajet of 1967. "Square bore" carburetors have primaries and secondary throttle bore sizes which are more nearly the same in size, but some have 1.44" primaries with up to 1.75" secondaries, generally. But no 2.25" secondaries.

Current AFBs and AVSs have the capability of bolting to both size of flanges on intake manifolds. The later Holley flange (1968 and later, OEM) will physically bolt to an aftermarket intake that is configured for "spreadbores", but only if the center divider in the intake, if there is one, is narrow enough to clear the larger primary throttle bores. The YouTube channel "318willrum" demonstrates how to convert a Chrysler factory spreadbore intake to one that will take any carburetor with the larger Holley flange. Actually quite easy with the proper tools!

Now, what I ALSO discovered is that an OEM-type Holley 4160 heat insulator carb base gasket for a Chevy truck DID work just fine on a spreadbore-configured aftermarket intake. It is stiff and strong enough to not need the more complicated "adapter" gasket the carb companies say you need. The rear engagement area might be thin, but no collapse over time (several years of use). Just as the current Street Demon carb is a spreadbore that uses the older "Holley flange" style. So, in that respect, what I'm terming the 1968+ OEM "Holley flange size" can also be a "Spreadbore flange size", also, although it didn't start out that way.

On the AFB, AVS, AVS2, or similar, the outside holes are for the later flange size, as the inside holes are for the 1967 and prior OEM manifolds. No matter the brand of the engine.

Hope this helps,
CBODY67

 

[CBODY67]

The 1967 normal 440 came with a Holley 4160? The local Chrysler dealer normally swapped out the "rebuild every year" OEM Holleys for similar year (no rebuild every year) AFBs back then. Kept their customers happy, that way. My '67 Newport 383 4bbl came with a "small pattern" AFB from the factory.

What number AFB is currently on your car?

Enjoy!
CBODY67