The Shocking Truth Behind Chevy’s Forgotten 173 CID V6 Engine – GM’s Most Underrated Engine!
Before names like the 3,100, 3,400, or 3,900 V6 became staples in GM’s lineup.
It all started with one humble engine, the 173 C in V 660°.
It wasn’t a powerhouse and it never became a racing legend.
But for millions of Americans who drove Chevy Estinis, Camaros or Pontiac Fieros in the 1980s, this small engine was the reliable heart that carried them through summers and long road trips.
So why did General Motors create this 60° V6?
Was it powerful enough to replace classic inline sixs and V8s?
And how did it become the foundation for an entire generation of GM engines that lasted nearly three decades?
Today, let’s rewind the forgotten history of one of GM’s most durable and quietly important engines ever built.
In the late 1970s, the American auto industry entered a new and challenging era.
Two consecutive oil crises, coupled with increasingly strict EPA emissions regulations, forced US car makers to rethink everything.
The big thirsty V8s that had once been a point of pride were now a liability, inefficient, and hard to keep within emissions limits.
In that environment, General Motors realized it had a major gap in its engine lineup.
It lacked a modern, lightweight V6 that was fuelefficient and versatile enough to power both front-wheel drive and rearwheel drive vehicles.
Previously, GM had relied on the Buick 2 31 CI in displacement V6, later known as the 3.8 L.
But its 90° design made it rough and ills suited for compact cars.
What GM needed was something smaller, smoother, and more scalable.
So in 1980, GM unveiled the 173 in V 660°, an allnew engine that first appeared in the Chevrolet Citation and other X body cars.
It was designed to become the foundation of GM’s future midsize and compact vehicles.
To bring that vision to life, GM needed an entirely new engine design.
One that wasn’t just technically and emissions compliant, but also compact, smooth, and versatile enough to fit multiple vehicle platforms.
And the engineers came up with the solution.
A 173 in V6 with a 60° bank angle.
A strategic, not accidental choice compared to 90° V6s.
The 60° layout offered much better balance, especially at low and mid-range RPMs.
Perfect for everyday driving.
This layout also made the engine narrower and better suited for compact front-wheel drive engine bays.
The engine featured a single overhead cam, hydraulic lifters, a longitudinal setup, and simple but easy to service construction.
The block was cast iron for durability, while later versions used aluminum heads to reduce weight.
Initially, this 173 CID engine came with a twobarrel carburetor.
GM later upgraded it to throttle body injection and eventually to multiport injection, all aimed at improving performance and meeting tightening emissions standards.
On paper, the 173 CD didn’t offer headline grabbing numbers.
Early versions with a twobarrel carburetor made about 110 horsepower and around 145 lb feet of torque.
But as the engine evolved with TBI and later MPI fuel injection, output climbed to around 130 to 135 horsepower and over 160 lb feet of torque.
Enough to provide stable performance both in city traffic and on the highway.
In practice, acceleration was moderate.
An early V6 Camaro took about 9 to 10 seconds to reach 0 to 60 mph, while the S10 or Blazer with the same engine felt peppier at low RPMs.
A plus for light truck applications.
But what most owners appreciated wasn’t the speed.
It was the smoothness, reliability, and reasonable fuel economy.
With a compression ratio between 8.5:1 and 9.0 to1, the engine ran happily on regular gas, wasn’t temperamental, and suited those who prioritize dependability over raw power.
In short, the 173 CI V6 wasn’t built to race.
It was built to serve.
And during the uncertain years of the early 1980s, that kind of steady performance was exactly what many Americans were looking for.
To ensure the engine kept up with evolving market demands and performance expectations, GM introduced several versions of the 173 CI in engine, each with its own engine code and a reflection of incremental engineering progress.
The first version coded LE2 was used from 1980 to 1981.
It featured a twobarrel Rochester carburetor and an 8.5 to1 compression ratio.
With an output of about 110 horsepower, it suited basic commuter cars, but lacked mid-range torque for more demanding applications.
From 1982 to 1984, GM launched the LH7, which included improvements to the cam shaft and ignition system.
Though it still used a carburetor, this version offered better throttle response and a modest bump in output to around 115 horsepower.
In 1985, GM introduced a major upgrade with the LB6, which brought in throttle body fuel injection.
This significantly improved torque delivery and everyday drivability, making the LB6 the most widely used version of the 173 cubic in engine.
Power ranged between 125 and 130 horsepower.
The final variant LL1 appeared from 1987 to 1989.
It featured a modern multiport injection system and improved ignition management.
This version pushed output to a peak of 135 horsepower, the highest in the engine’s life cycle.
With its steadily evolving engineering foundation, the 173 cubic in displacement was soon adopted across a wide range of GM vehicles from sporty coups to family sedans and compact pickups.
One of the first vehicles to use the engine was the Chevrolet Citation, which pioneered the front-wheel drive Xbody platform.
With its compact design and mid-range displacement, the 173 cubic in V6 was a sensible choice for compact cars that needed more power than a standard 4 cylinder.
The 1982 to 1985 Chevrolet Camaro also marked a major milestone.
This generation was the first to feature the new F-body chassis and also the first to offer a V6 instead of the traditional inline 6.
While not as powerful as the V8 variants, the V6 model appealed to drivers looking for everyday usability, better fuel economy, and lighter handling.
In the sport compact category, the Pontiac Fiero GT from 1985 stands out.
Originally criticized for its underpowered 4-cylinder, the Fiero became a much more exciting car when fitted with the 173 cubic in V6.
It offered improved acceleration, a sportier exhaust note, and more confidence on the road.
On the light truck side, the Chevrolet S10 and Blazer were two popular models powered by this engine.
With sufficient low-end torque and a compact footprint, the 173 cubic in V6 was ideal for small pickups and SUVs that had to balance daily drivability with occasional utility tasks.
Although widely regarded as one of GM’s most reliable mainstream V6 engines of the 1980s, the 173 CID wasn’t without its share of flaws, especially in its early iterations.
One of the most frequent issues was coolant leakage around the cylinder heads, often caused by poor quality gaskets or thermal expansion differences between the aluminum heads and cast iron block.
If left unchecked, this could lead to overheating, cracked heads, or more severe internal damage.
Another common complaint involved premature cam shaft wear, particularly on early LE2 and LH7 versions.
These engines had relatively high cam shaft loads, but lacked adequate low RPM lubrication.
Infrequent oil changes only made matters worse.
Some mid80s TBI equipped versions also suffered from faulty sensors, resulting in rough idling, hard starts, or inconsistent RPM behavior.
Fortunately, most of these technical issues could be prevented with regular maintenance, changing oil on schedule, using the correct type, and keeping the cooling system in good shape.
Many veteran mechanics have said, “This engine isn’t meant to race, but take care of it, and it won’t leave you stranded.”
In terms of driving feel, some drivers felt the engine lacked high-end power, especially in sportier models like the Fiero or Camaro.
Still, for those who prioritize durability, quiet operation, and ease of repair, the 173 CI in V6 remained a respectable choice for its time.
But that technical foundation allowed GM to develop a V6 lineage that would span three decades, beginning with the humble 173 cubic in displacement.
Its core layout with a 60deree bank angle, single overhead cam, compact block, and high adaptability became the basis for an entire family of V6 engines GM would go on to build.
Soon after the 173 CID was phased out in 1989, GM introduced the upgraded 191c version featured in vehicles like the Chevrolet Luminina, Pontiac Grand Prix, and Oldsmobile Cutless Supreme.
That engine continued evolving into larger variants such as the 207 CID, 214 CID, and eventually the 237 CID.
In the 2000s.
Although later versions incorporated more advanced technologies like dual overhead cams, modern sensors, and variable intake systems, their core engineering still echoed the original 173 CID.
In fact, components like the engine block, crankshaft, and bearing layout remained largely unchanged, a rarity in the fastmoving world of engine design.
Because of that durable core design, the 173 in V6 still maintains a quiet but steady presence in today’s American car culture, particularly among vintage restoration and retro mod enthusiasts.
While it’s far from ideal for high performance builds, the engine is still valued by purists who place authenticity and historical accuracy above speed or horsepower.
Many owners choose to restore their Chevrolet S10s, Pontiac Fiero GTS, or third gen Camaros using the original 173 CID engine.
Not because it’s powerful, but because it’s part of the story.
Every nut and bolt in those engines tells of a time when cars were simpler and more personal.
Some hobbyists also use the 173c block as a base to install parts from the 207 or 214c variants thanks to their high degree of interchangeability.
At local car shows or small town meets, these modest machines restored with care and honesty often draw admiring looks, not for their power, but for their respect for the past.
The 173 CIDV6 may have never graced magazine covers or made it onto lists of legendary engines, but for nearly a decade, it quietly served millions of Americans.
From S10 drivers commuting to work to young enthusiasts behind the wheel of their first V6 Camaro, it didn’t roar like a V8 or thrill like a turbo, but it embodied something very American.
Practicality, durability, and quiet loyalty.
