Quadrajet Date Question

[72 Cheyenne K20]

I have a Rochester Quadrajet number 7043208 with a date code of 1538 on my truck when I bought it. All of the engine is original except for this.

From the number 7043 it’s from a 73’ but the date code indicates 153rd day of 68’ or 78’.

Does anyone have a clue or seen this happen before?

Thanks, Scott

[geezer#99]

Since the casting number starts with a 7 and not a 1 that would indicate the carb is pre 1976. The number 1 at first place started in 76.
Your 8 would be 1968 then.

[Corts60]

1965-69 carbs would've started with a 702 or 703. Since yours starts with 704, it is a 70-75 carb. The 4th digit is the year. In your case a "3" is 1973.

breakdown:
704
3 = 1973
2 = federal emissions
0 = Chevy
8 = even number usually means auto trans, but not always

As for the date being 1538, most likely this was a factory service replacement carb that was installed in 1978 or later, maybe under warranty.

[72 Cheyenne K20]

Hi guys and thanks for the replies.

I understand the cast dating but wanted to know if anyone has any reasoning for the model cast number to not match the date cast number.

7043 = 1973
1538 = 1968 or 1978

The last number in the date should be a 3 to match the 7043

So, I was thinking maybe they got the date mixed up and it should be 1583 instead ?

Thanks Scott

[Corts60]

Originally Posted by 72 Cheyenne K20

Hi guys and thanks for the replies.

I understand the cast dating but wanted to know if anyone has any reasoning for the model cast number to not match the date cast number.

7043 = 1973
1538 = 1968 or 1978

The last number in the date should be a 3 to match the 7043

So, I was thinking maybe they got the date mixed up and it should be 1583 instead ?

Thanks Scott

Yep, I hear ya, the model cast date and Julian date are different when the carb is a factory service replacement. Meaning the original carb probably had a repeat issue and the dealer installed this carb as a replacement. So, 1538 probably indicates the year this carb was installed, or 1978.