I just bought a 1977 Automatic L48 . It currently has a Holly Spreadbore Carb thats atleast 23 years old. I want to put the original make carb that it came new with back on it. Can anyone tell me what exact Carburetor came with them back in 1977? I know it was a Rochester but could someone tell me the model number or part number?

Thanks for any help!

I believe most C3s came with the Rochester Quadra-Jet carbs.  My '70 originally had one from the factory but a previous owner had replaced it with a Holley spread bore.  I'm sure someone else will have a better answer for you.

Try calling Cliff Ruggles at cliffshighperformance.com.  He literally wrote the book on Q-jets.

'77 automatic with A/C should be a Quadrajet #1705204. If you look for one, the part number is located on the driver side rear of the carb. Depending on the manufacturer(some were made by Carter, most by Rochester), the number may or may not start with 170xxxx...some only have a 70xxx as the first numbers. The build date code is in that same spot.

Greetings, I believe there is a number missing in the last post. The Rochester number for a 1977 auto with AC is 17057204. ALL Rochester numbers AFTER 1975, started with "1". 1975 and earlier started with "7". This should help in finding a correct unit. 

Greetings again.  As another factor for finding a correct unit, the "7" in the number, 5th digit, designates the year of the car in which the carburator was installed. The number that was missing is the year.

No Problem.  We're here to help. Together  Everyone Achieves More. 

Good catch Mark!! Old man typo....🤓