3247 Carb Metering Blocks ??

[Larry T.]

I believed that the proper metering blocks for a 3247 carb were 4901 - front and 4519 - rear. I am looking at a carb with a 502 date that has those block. I have also been told that early 3247 carbs had a different front block. Is that correct? I am most concerned with carbs dated September or October 1965. If someone could clear this up and let me know when it changed I would appreciate it. And if anyone has an extra one of these (September or October 1965) laying around I would love to talk to you.

[Michael H.]

Re: 3247 Carb Metering Blocks ??

I believed that the proper metering blocks for a 3247 carb were 4901 - front and 4519 - rear. I am looking at a carb with a 502 date that has those block. I have also been told that early 3247 carbs had a different front block. Is that correct? I am most concerned with carbs dated September or October 1965. If someone could clear this up and let me know when it changed I would appreciate it. And if anyone has an extra one of these (September or October 1965) laying around I would love to talk to you.

Larry,

Supposedly, there was a 1st and 2nd design primary metering body for the 3247 Carburetor.
Although I've never seen one, the 1st design body is/was GM #3889788 and Holley # 34R4746.
The 2nd design was GM #3893667 and Holley #34R4901.

I have no information as far as when the change occured or what the difference was between these two parts. I would assume some minor calibration correction and it likely occured very early in production.

By the way, it's likely very early 3247 carburetors used the same fuel bowls as those used on the 1965 396 engine with the small inlet fittings.

[Wayne M.]

Re: 3247 Carb Metering Blocks ??

I believed that the proper metering blocks for a 3247 carb were 4901 - front and 4519 - rear. .... I have also been told that early 3247 carbs had a different front block. .... I am most concerned with carbs dated September or October 1965. If someone could clear this up and let me know when it changed I would appreciate it. And if anyone has an extra one of these (September or October 1965) laying around I would love to talk to you.

In the Fall 1992 issue of the RESTORER Gary Hodges lists Holley data (models, I.D. #, metering blocks, bowls, etc. He shows early metering blocks as being stamped with # 4746 (the last 4 digits of the long Holley part # Michael shows). The secondary remains the same early/late at 4519.

Other than that, there's a tech service bulletin dated 2/15/66 to "correct an "early" 427 Corvette surge during light acceleration between 40 and 50 mph. Change out #63 main jets on carbs with build code 594 and earlier with #65 jets". (ie. date code 4th week of September, 1965)

I don't know if the factory change in a jet size would necessitate a numbering change in the meter block assy; maybe others could comment.

[John C.]

Re: 3247 Carb Metering Blocks ??

If anyone has an extra Sept. - Oct . 3247 laying around I can use one . REALY.
John Cook

[Larry T.]

Re: 3247 Carb Metering Blocks ??

That is a fact.

If anyone has an extra Sept. - Oct . 3247 laying around I can use one . REALY.
John Cook