Help with chevy carb numbers

Willowbilly3 · Jul 31, 2012

I have a Holley carb I am trying to decipher. It has a GM part number 3959164-GE and a list number 4346. I have found that it is a 4150, 780 cfm and originally from a 375 horse 396 or a 425 horse 427. What doesn't make sense is the date code. It is supposed to be 3 digits and its 4, 1597. I can't make any sense of that date code, can any of you?

Dr Crankenstein · Jul 31, 2012

I did some digging and here's what I found...

- Holley 4 digit date codes began in 1973 and used the Julian calendar.

- Date code 1597: 159th day of the year - 7th year of the decade. (June 1977)

- What you have is a service replacement carb for the GM part number. Same carburetor, same specs, but not the original.

Willowbilly3 · Jul 31, 2012

But neither of those engines existed by 1977???

Dr Crankenstein · Aug 1, 2012

Right. The GM number is correct for a 1969 engine as you already know. The date code is a carb made 8 years later as a direct replacement for the original.

So it's 1978. You need a carb for your 427 or 396. You run down to your Chevy dealer and he gives you a Holley with the numbers you have. Correct part number, correct list number, later date number.