What engine is in a 1991 S10 Blazer?
The 1991 Chevrolet S-10 Blazer could be equipped with one of three engines: a 2.5L inline-four, a 2.8L V6, or a 4.3L V6, depending on the model and option package.
In this year, Chevrolet offered a range of powertrains for the S-10 Blazer to suit different buyers—from basic daily driving to light towing and tougher off-road use. The choice of engine typically aligned with the trim level and whether the vehicle was configured for everyday commuting or work/utility tasks. Below is a concise guide to the common engine options for US-spec 1991 Blazers and how they compared.
Engine options for 1991 S-10 Blazer
The following list outlines the main factory engine choices that could appear under the hood of a 1991 S-10 Blazer. Availability varied by trim and market, with the inline-four generally serving as the base option and the V6 engines offering more power for towing and adverse terrain.
- 2.5L inline-four (Iron Duke) — roughly 105–120 horsepower, with torque around 130–140 lb-ft; typically paired with a manual or automatic transmission depending on configuration.
- 2.8L V6 — roughly 125–140 horsepower, with torque around 150–165 lb-ft; commonly paired with a 4-speed automatic or a manual in certain setups.
- 4.3L V6 — roughly 165–190 horsepower, with torque around 250–270 lb-ft; the most common choice for higher-trim Blazers needing more pulling power, usually mated to an automatic transmission.
Notes: Engine outputs varied by emission controls, fuel delivery system (carbureted vs. fuel-injected), and specific calibration for the model year. The 4.3L V6 was widely used across GM trucks and SUVs and is the most performance-oriented option among the three.
Engine specifics by option
2.5L inline-four Iron Duke
The 2.5L I4 served as the base powerplant for many early S-10 Blazers. It offered modest performance suitable for everyday driving and light-duty work, with an emphasis on fuel economy relative to the V6 options. Horsepower typically hovered in the low hundreds and torque was moderate, making it adequate for city and highway use but less capable for towing or heavy loads.
2.8L V6
The 2.8L V6 provided a noticeable upgrade in smoothness and mid-range response over the four-cylinder. It delivered more torque, improving acceleration and the ability to handle modest towing or payloads, while still maintaining reasonable fuel efficiency for a family SUV of the era.
4.3L V6
The 4.3L V6 was the strongest engine option offered for the 1991 S-10 Blazer, delivering robust torque that benefited hill climbs, towing, and off-road use. Depending on the exact configuration and fuel system, power ranged from the mid-160s to near 190 horsepower, with torque typically well above 250 lb-ft. This engine was commonly paired with an automatic transmission to maximize pulling power and drivability.
Transmission considerations
Engine choice often determined the available transmissions. Base setups frequently used a manual gearbox, while higher-trim models more commonly paired with a 4-speed automatic (and later models sometimes featured overdrive-equipped automatics). The 4.3L V6 was routinely paired with automatic transmissions to best utilize its torque for towing and load-bearing tasks.
Summary
For the 1991 S-10 Blazer, there were three primary engine options: the 2.5L inline-four, the 2.8L V6, and the 4.3L V6. The base 2.5L prioritizes economy, the 2.8L offers a balance of power and efficiency, and the 4.3L V6 delivers the strongest performance for towing and tougher driving conditions. Buyers’ choices depended on their intended use, with the 4.3L V6 serving as the standout for those needing more capability.
In short, a 1991 S-10 Blazer could have several engine configurations under the hood, with the three main options described above representing the typical lineup for that model year.
Summary: The 1991 S-10 Blazer did not have a single engine; it offered multiple powertrains to fit different needs, with the 4.3L V6 as the standout for higher performance and towing potential.
