How to Identify Your Rochester B Carburetor for the Right Rebuild Kit
If you are restoring a classic 1932–1960s Chevy, GMC, or Oldsmobile inline-6, there is a very good chance you are staring at a Rochester B-series carburetor. First introduced in 1950, this single-barrel workhorse became a staple of vintage American automotive history.
However, ordering a rebuild kit isn’t as simple as just buying a "Rochester B kit." Over its long production run, the Rochester B underwent numerous internal changes, gasket variations, and design updates. To make matters trickier, the B family actually consists of three distinct models:
Model B: Manual choke.
Model BC: Automatic (automatic/heat-tube) choke.
Model BV: Vacuum-assisted choke.
Ordering the wrong kit can result in mismatched gaskets, incorrect needle valves, or missing accelerator pumps. Here is exactly how to identify your specific Rochester B carburetor to ensure you get the perfect rebuild kit the first time.
Method 1: Locate the Original Carburetor Tag (The Gold Standard)
The absolute foolproof way to identify a Rochester carburetor is by its original identification tag.
Unlike later carburetors that had numbers stamped directly into the metal body, Rochester B carburetors used a small, triangular aluminum or brass tag held down by one of the air horn (top cover) screws.
What to Look For:
If your tag is still intact, look for a 7-digit number (usually starting with a 70 or 1). Examples include numbers like 7002050 or 7004475.
When shopping for a rebuild kit, cross-referencing this exact 7-digit number with the manufacturer's compatibility list guarantees a 100% accurate match.
The Reality Check: Because these tags were flimsy and easily lost during previous rebuilds over the last 70 years, a vast majority of Rochester B carburetors on the road today are missing their tags. If yours is gone, don't panic—move on to Method 2.
Method 1: Locate the Original Carburetor Tag (The Gold Standard)
