Can anyone confirm this is a large base? I'm new to carbs so excuse my ignorance. From what I have read and measured they seem to my large base instead of small.
The base. Not the bowl. If I recall correctly bolt pattern on base is about 2x3 3/4 center to center.
I think I'm not follow on base. You said base of the carb which I ***ume is the bottom and that's what I sent. So now I'm ***uming you meant the base plates under the carbs which are these
those look like small base, you need to measure The name "big base" refers to the bolt pattern. The big being 2" x 3 3/4" bolt hole center to center.
Okay I'm not follow in which bolt pattern because there is a few places to measure off of. I'm a visual person
The first pic clearly shows a small base 2G with a truck manual choke top. 55-58 were front fuel inlet and 59-73 side inlet like one pictured. 55-68 no numbers stamped on the right front 69-73 were stamped. Avoid later ones as lots of air bleeds for leaner mixture and emissions requirements. I build custom tri-power sets with small base Rochesters. Reach out if you have more questions. Link to one of my vintage induction systems for reference. https://www.jalopyjournal.com/forum/threads/custom-rochester-2g-tri-power.1322343/#post-15382749
Wes - there are three major castings used on the Rochester 2G series carburetors. From top to bottom: Airhorn - commonly referred to as the top. Bowl - commonly referred to as center section or main body Throttle body - commonly referred to as the base There are two COMMON mounting patterns of the non-Ford two-barrel carburetors. "Small" measures 1 7/8 inches front to rear, and 3 1/4 inches from side to side. "Large" measures 2 inches front to rear, and 3 11/16 inches side to side. What is being measured is the center to center distance of the bolts holding the throttle body to the intake manifold. Jon
Thank you everyone! I wasn't aware the base plates were considered part of the carb. I have been measuring the three bolt holes on the actual carb.
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