The choice between a Cessna 172 fitted with a 180-horsepower conversion and a stock Cessna 182 represents one of the most enduring debates in the piston single-engine ownership community, and the original poster's breakdown captures the core tradeoffs accurately. A 172 converted with a Lycoming O-360 (via STCs from providers like Air Plains, Penn Yan Aero, or similar shops) typically closes much of the performance gap with the 182's factory Continental O-470, yet does so with a four-cylinder engine that generally costs less to overhaul and maintain than the six-cylinder Continental found in the 182. Useful load, often cited as the primary reason buyers step up to a 182, ends up being closer between the two airframes than commonly assumed once the conversion's lighter engine and simpler systems are factored in, since the O-470 adds weight up front that partially offsets its extra horsepower.
For working pilots and aircraft owners, this comparison matters because it sits at the intersection of acquisition cost, operating cost, and mission utility, three variables that drive nearly every decision in the light GA fleet. Flight schools and CFIs evaluating fleet aircraft for primary and instrument training care about fuel burn per hour and engine reliability just as much as private owners weighing a family cross-country airplane, since both groups are ultimately optimizing dollars per flight hour against mission requirements. The 182's larger production numbers, noted correctly in the post, translate into a deeper used market with more airframes to choose from, more parts commonality, and generally better liquidity at resale, which is a real consideration for owners who may need to sell in a downturn or upgrade later. Converted 172s, by contrast, are a smaller and more idiosyncratic market where buyers must vet the specific STC, the shop that performed the conversion, and the completeness of paperwork, adding due-diligence overhead that a stock 182 buyer largely avoids.
The engine maintenance point deserves particular emphasis for anyone doing real ownership-cost math. Continental O-470 overhauls tend to run more expensive than Lycoming O-360 overhauls, both in parts and labor, and the O-470's six-cylinder configuration statistically presents more opportunities for cylinder and accessory issues over a TBO cycle. This dovetails with a broader trend across owner-flown GA: buyers increasingly prioritize simpler, four-cylinder Lycoming powerplants (O-320s and O-360s) over six-cylinder Continentals specifically because parts availability, shop familiarity, and overhaul cost favor the Lycoming line in today's market. Rising avgas prices have also pushed more owners toward mogas-compatible STCs, which are more readily available and cheaper to certify on the O-360 than on the O-470, giving the converted 172 an additional economic edge for pilots flying in regions with auto-fuel access.
Where the 182 still earns its premium is in useful load ceiling for gross weight operations, gear/flap speed margins, and a factory-supported airframe that many insurers and mechanics know intimately, which can translate into smoother insurance underwriting and more predictable annuals. This debate reflects a larger pattern in the legacy piston fleet, where buyers are increasingly parsing marginal performance differences against total cost of ownership rather than defaulting to the "bigger engine, more capability" assumption that dominated GA purchasing decisions in past decades. As the used aircraft market continues to tighten and overhaul costs climb across the board, discussions like this one are likely to become more common, with owners and flight departments alike scrutinizing horsepower-per-dollar and cylinder count as seriously as they scrutinize avionics and airframe condition.