1965 GM Rochester Carbs

[Tom R.]

I need some education on C2 Rochester carbs. Perhaps generally, but more specifically, a 1965 Olds 442 carb configured for automatic. I see no part numbers or date codes and wondering back in the 1960s, did GM use the metal tags for that type of information?

The story is my brother in-law has a 442 convertible with blown engine and "service replacement" carb while the original power team items are on the shelf. I got looking at the carb which is quite different than what I see regularly with C3 years...thus my curiosity. Here are a few pictures. He claims its a survivor but I describe for him in the collector car world what a survivor is...one with the original in tact...operating the vehicle and an interior that has not been altered from vinyl/leather to cloth.

Thanks!

[James G.]

Re: 1965 GM Rochester Carbs

See page 151 in CHEVROLET BY THE NUMBERS, 1965-1969 by Alvin L. Colvin. He explains that this is the first QUADRAJET carb. There were two styles of 4MV and 4 MC. The 4MV choke is mounted to the manifold mounted choke coil. The 4MC has the choke mounted to the side of the float bowl.

Rochester used two different tags to identify the model. The tag had the model number [7027110], and change letter [A] then YEAR AND MONTH [A7] and finally an inspection #.

A 4 MV for a 65 big block passanger 396/ 325hp is listed as a 7025200 early. Same family of 7025201, and 7025221 late. I don't have Oldsmobile, but I am sure their spec sheets have a similar carb.

[Peter M.]

Re: 1965 GM Rochester Carbs

Tom,
I think the carb in the picture is a Rochester "4GC". I think the 4 MV/MC that Jim is referencing is the Quadrajet or spread bore carb. As Jim mentioned 1965 seemed to be when the spread bore Rochesters started to show up.
I have access to some old Rochester information, if you would like I can try and find a part number and description for the 442 carb.
Kind regards

[Joe L.]

Re: 1965 GM Rochester Carbs

Tom,
I think the carb in the picture is a Rochester "4GC". I think the 4 MV/MC that Jim is referencing is the Quadrajet or spread bore carb. As Jim mentioned 1965 seemed to be when the spread bore Rochesters started to show up.
I have access to some old Rochester information, if you would like I can try and find a part number and description for the 442 carb.
Kind regards

Peter------


The carb pictured is definitely a Rochester 4 GC. This carb was widely used on GM vehicles, although never Corvettes, prior to the introduction of the Quadrajet. Among other identifying features, note the cast iron throttle body. I know of no Q-Jet that ever used a cast iron throttle body.

[Tom R.]

Re: 1965 GM Rochester Carbs

Tom,
I think the carb in the picture is a Rochester "4GC". I think the 4 MV/MC that Jim is referencing is the Quadrajet or spread bore carb. As Jim mentioned 1965 seemed to be when the spread bore Rochesters started to show up.
I have access to some old Rochester information, if you would like I can try and find a part number and description for the 442 carb.
Kind regards

Yes that would be helpful

And JL's comment:

The carb pictured is definitely a Rochester 4 GC. This carb was widely used on GM vehicles, although never Corvettes, prior to the introduction of the Quadrajet. Among other identifying features, note the cast iron throttle body. I know of no Q-Jet that ever used a cast iron throttle body.

Offers additional confirmation about the configuration of the 4GC carb.

thank you all

[Jeff B.]

Re: 1965 GM Rochester Carbs

Yes, this carb is a 4GC. It is Rochester's version of the Carter WCFB. Never used on Corvettes, but many other GM models that could have had either a WCFB or the 4GC.

[Peter M.]

Re: 1965 GM Rochester Carbs

Tom,
7025150 manual or automatic w/o air conditioning.
7025151 manual or automatic with air conditioning.
Regards

[Tom R.]

Re: 1965 GM Rochester Carbs

Tom,
7025150 manual or automatic w/o air conditioning.
7025151 manual or automatic with air conditioning.
Regards

Thanks Peter!