C2: 66 425 HP #3247 Holley Carburetor

[Michael H.]

Does anyone have an original VERY early #3247 Holley carburetor for a 66 425 HP 427? I'm looking for information on the stamped number on the pri and sec metering bodies.

Also, does anyone happen to have a first printing of the 66 parts book? (Aug 65?) Need info, or preferably, a scan of the group 3.734 page. The information in my July 66 printing does not have the original part numbers for the metering bodies and fuel bowls that I'm looking for. It lists 1st design pri metering body as a #4746 but it's very confusing on the sec body number. I believe both pri and sec bodies changed number some time into 66 production. (March?)

I have reason to believe that very early #3247's used the same fuel bowls that were used on the 1965 #3124 carburetor for 396 with the small fuel inlet fittings. Anyone ever see these early style bowls on a #3247?

[Mike M.]

Re: C2: 66 425 HP #3247 Holley Carburetor

i had a 3247 off of a pre 1K vin 66 and it didn't have the 65 style fuel bowls . i no longer have the car so i can't state the stamp date on the holly..mike

[Joe L.]

Re: C2: 66 425 HP #3247 Holley Carburetor

Michael-----

The primary metering body assembly first used for the 1966 3247 carb was of GM #3889788. This metering body was stamped "4746". The GM #3889788 was not supercessive to any other part number. So, there was no "predecessor" to the 3889788; it was the "first one" used for the 3247 carb.

Sometime later in the model year the part changed to GM #3893667 which was stamped "4901". Just when this change occurred, I do not know and it's not revealed in any parts information.

Although it is poorly catalogued, the secondary fuel metering body for the 3247 carburetor was GM #3877171. It was stamped "4519" and was the same unit used for the 1965 Corvette 3124 carb, as well as others. It was not supercessive to any other part number and was never superceded by any other part number. It was discontinued without supercession in August, 1978.

[Michael H.]

Re: C2: 66 425 HP #3247 Holley Carburetor

Thanks Mike. I have a poor quality pic of a new very early 425 HP that's from a car magazine road test and it appears to have the 65 style bowls and fittings but it's difficult to tell for sure. I don't remember the magazine but it's probably Hot Rod or some similar publication. The air cleaner assy is off and sitting on the fender. It has a black painted cover and no HP decal which I believe would be correct for that early car.

Years ago, someone asked me if I thought the 65 style bowls could be correct for an early build but I could never find any documentation on it. He claimed his car/carburetor were all original and a 2nd week build.

I'll try to post the pic later.

[Michael H.]

Re: C2: 66 425 HP #3247 Holley Carburetor

Thanks Joe,

The primary metering body part number info seems to agree with my later 66 printing. It shows both first and second design but one number is shown as a secondary, not a primary. I suspect this is a misprint. I'll try to scan/post the page later tonight.

Does your early 65 printing show the original number for the fuel bowls? In the July 66 printing, the original bowl numbers are replaced with the 66 numbers. I'm surprised the original 65 bowls discontinued that quickly.

[Joe L.]

Re: C2: 66 425 HP #3247 Holley Carburetor

Michael------

I'm not even sure that the numbers for the fuel bowls shown in the first P&A Catalog published with 1966 parts information (October 1, 1966) are accurate. It shows both GM #3889781 and GM #3889784 as SECONDARY fuel bowls for the L-72 carburetor with no listing, at all, for a primary fuel bowl for the L-72 carb. However, I believe that the 3889781 is actually a primary fuel bowl, though, and the catalog is incorrect showing it as secondary.

GM #3889781 had a predecessor part number and that number was GM #3881427. GM #3881427 was the fuel bowl catalogued as of July 1, 1965 for the 1965 L-78 in both passenger cars and Corvettes. However, the 1965 passenger car carb (3130) did not actually use the same fuel bowls as the Corvette (3124). GM #3881427 had no predecessor part number.

The GM #3889784 had no predecessor part number.

[Michael H.]

Re: C2: 66 425 HP #3247 Holley Carburetor

Joe,

That's interesting. I would have guessed the original bowls for the 3124 would be closer to the numbers of the carburetor itself. (3868xxx-3877xxx)

Also of interest it the fact that the front bowl from a 66 3247 would not make a good replacement for the 3124 as the 3124 had no external bowl vent but the 3247 did.

I think the folks that gathered/arranged the carburetor information for 65-66 were VERY confused.

I agree, I've always thought the 3889781 had to be a primary, not a secondary. I made that note in my parts book decades ago.

I tried to order one each of every number about 30 years ago but only one bowl ever showed up. No metering bodies.

Also, my July 66 printing shows no unique part number for the 65 only fuel bowl fitting. It lists the fitting as being the same as 66 and later but that part won't fit an original 65 bowl.

[Michael H.]

Re: C2: 66 425 HP #3247 Holley Carburetor

Joe,

Page from July 66 parts book. Does this agree with your October 65 printing? Does the 65 have the same errors? The bowls are listed on the top and metering bodies below.

[Wayne M.]

Oct 1, 1965 printing (2 pages)

This is from the big 1670 page book. Tried to follow you guys but it was too complicated.

Click link below this image for continuation on page 2. May have to zoom to read.

[Michael H.]

Re: Oct 1, 1965 printing (2 pages)

Thanks Wayne,

Looks like the original 1st design #3247 Holley was indeed equipped with a #4746 primary metering body and a #4519 secondary metering body.

The 2nd design #3247 would have been equipped with a #4901 Primary metering body and the same #4519 secondary metering body.

Your parts book must have been an early printing as there is no mention of the 2nd design 3893667 (#4901) primary metering body.

As Joe mentioned, there's no way to tell exactly when this change occured but the number change in my book was shown as March 1966, although that doesn't necessarily mean that's when the change occured in production. I suspect it occured much earlier, possibly in the first or second month of production.

One down. Now, about those weird 65 style float bowls on very early 66 3247's.