When it comes to restoring or verifying the originality of your Chevelle, correctly identifying the small block under the hood an important step. After all, the engine under the hood is what makes a Muscle Car, a Muscle Car! From 1964 through 1972, Chevrolet offered a variety of small block V8s in the Chevelle lineup, ranging from the 283 to the high-revving 302, the popular 327, the 307, and eventually the legendary 350.
While all of these engines fall under the “Small Block Chevy” family, not all are created equal and the casting numbers and suffix codes will help you identify exactly what you’re working with.
How to Identify a Small Block in Your Chevelle
There are two key number sets used to identify a small block Chevy engine:
1. Casting Numbers
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These are cast into the block at the foundry and located on the driver’s side rear of the block, just forward of the bellhousing flange.
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Casting numbers tell you the basic engine family, displacement, and production years.
2. Stamped Numbers
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These are stamped into a machined pad on the block, usually located in front of the passenger-side cylinder head, often hidden under the alternator.
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These include a plant code, assembly date, and most importantly, the suffix code, which tells you the original vehicle application, transmission type, and horsepower rating.
Note: If the block has been decked (machined flat), the stamped pad may be blank, making ID more difficult.
Example Stamped Engine Code:
V0101CLJ
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V = Flint Engine Plant
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01 = January
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01 = 1st Day
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CLJ = Suffix code (decode for original specs)
Common Engine Plant Codes Found in Chevelles:
| Code | Plant Location |
|---|---|
| F | Flint (Motor Division) |
| V | Flint (Engine Plant) |
| T | Tonawanda |
| K | St. Catharines, Ontario |
| M | GM Mexico |
Small Block Casting Date Example:
E038
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E = May
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03 = 3rd Day
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8 = Last digit of year (1968)
Month Code Reference:
A = Jan, B = Feb, C = Mar, D = Apr, E = May, F = Jun, G = Jul, H = Aug, I = Sep, J = Oct, K = Nov, L = Dec
Most Common Small Block Chevelle Engines (1964–1972)
| Casting Number | CID | Years Used | Horsepower Range | Notes |
|---|---|---|---|---|
| 3782870 | 327 | 1962–65 | 250–375 hp | High-performance L79 engine |
| 3791362 | 327 | 1964–67 | 250–300 hp | Often used in SS and Malibu |
| 3849852 | 283 | 1964–68 | 195–220 hp | Found in base models and wagons |
| 3855961 | 350 | 1968–76 | Varies | First year for 350 in Chevelle |
| 3914660 | 327 | 1968 | 210–300 hp | Final year for 327 |
| 3970010 | 350 | 1969–79 | 185–370 hp | High-performance & base engines |
| 3932386/388 | 302/350 | 1969 | 290–350 hp | Z/28 and high-performance apps |
| 3970024 | 307 | 1969–72 | 130–200 hp | Base engine on many models |
Note: Chevelles didn’t get the 400 small block from the factory during these years — if you see one, it’s a transplant.
How to Decode Your Suffix Code
The suffix code (e.g. “CTY”) tells you specifics like:
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Engine size
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Transmission (manual or auto)
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Horsepower rating
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Original vehicle (Chevelle, Camaro, etc.)
For a full list of suffix codes specific to your engine’s year, check out NastyZ28.com’s Suffix Code Chart.
Final Notes
When identifying a small block engine in your Chevelle, the casting number and date will provide general information about the engine’s size and production range, while the stamped code offers specific details such as the original vehicle application, horsepower rating, and transmission type. Matching both the casting and stamped codes to your Chevelle’s VIN and trim tag can help determine if the engine is original or “numbers matching.” However, if the block has been decked, meaning the top surface was machined flat during rebuilding, the stamped ID pad may be blank, making it harder to verify originality. In such cases, you’ll need to rely on casting numbers, date codes, and internal components to identify the engine accurately.
Additional Resources:
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ChevelleStuff.net – great for decoding VINs and engine data
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NastyZ28.com – deep suffix code database
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Mortec.com – casting number references
If you need any parts for your small-block or Chevelle, hop on SS396.com or give our friendly techs a call at (203) 235-1200!
