They were born in the same factory, designed for the same market, and carry the same pressurised cabin promise: climb above the weather, arrive rested, cover 800 nautical miles before lunch. But the Cessna 340 and the Cessna 421 Golden Eagle are fundamentally different aircraft beneath the cowlings — and that difference shapes everything from your purchase price to your bank account every 1,400 hours.

We have 838 real transactions from the last 18 months in our database. Here is what they actually tell you about the 340 vs 421 decision.

What the Cessna 340 Is

The 340 entered production in 1972 as Cessna's entry-level pressurised twin — a step above the unpressurised 310 for owner-pilots who wanted cabin altitude comfort without the operating complexity of the larger Golden Eagle. It was built through 1984, with approximately 1,287 delivered in total. The 340A variant ran from 1976 with intercooling, revised pressurisation, and improved systems.

Power comes from two Continental TSIO-520 engines producing 285–310 hp per side. Turbo-supercharged and intercooled on the 340A, they are conventional gearless engines — meaning the propellers turn at essentially the same speed as the crankshaft. That distinction matters more than most buyers realise.

Performance at a glance:

Cruise speed: 195–205 knots true (depending on altitude and power setting)
Service ceiling: 29,800 ft
Cabin altitude at FL250: approximately 8,000 ft
Range: 900–1,050 nm with reserves
Max passengers: 6

If you're buying, the 340A is almost always the right choice over the original 340. The intercooling improvement is meaningful, and later examples are better-sorted aircraft.

Browse Cessna 340A listings on Sprinkle →

What the Cessna 421 (Golden Eagle) Is

The 421 has been built since 1967 and represents the top of Cessna's pressurised piston line — bigger, faster, and considerably more complex than the 340. The 421C (introduced 1975) is the definitive variant. Production ran until 1985.

The 421 is a proper cabin-class aircraft: 55-inch-wide body, club seating, galley option, seating for up to eight. And its engines are the thing that defines ownership.

The 421C uses Continental GTSIO-520 engines producing 375 hp per side — geared turbosupercharged units where a reduction gearbox sits between the crankshaft and propeller. The gear allows the engine to produce more power at lower propeller RPM, delivering two real-world benefits: a quieter cabin and more efficient high-altitude cruise.

But the gear is also the 421's original sin. More on that shortly.

Performance at a glance:

Cruise speed: 210–225 knots true (at altitude)
Service ceiling: 30,200 ft
Cabin altitude at FL250: approximately 8,000 ft
Range: 1,000–1,200 nm with reserves
Max passengers: 8

Browse Cessna 421C listings on Sprinkle →

The Engine Question — This Is the Real Decision

Buyers who research the 340 vs 421 debate long enough almost always arrive at the same crossroads: the 421's geared engines define the ownership experience, for better and for worse.

The TSIO-520 in the 340A is one of the most common Continental engines ever built. Overhauls from reputable shops run approximately $50,000–$65,000 per engine at TBO. The TBO is 1,600 hours. The engine has a long service history, a wide network of qualified shops, and established parts availability. It rewards competent management and punishes neglect — but it is not exotic.

The GTSIO-520 in the 421C is a different proposition entirely. Overhaul costs run materially higher — experienced operators budget $90,000–$150,000+ per engine. TBO is 1,200–1,600 hours depending on variant, and actual time to overhaul is often shorter in practice because geared engines are sensitive to torque loading and management technique. The gearbox adds a failure mode not present in the 340. Case cracking — caused by running the engine rich of peak rather than lean of peak — has historically been a problem in this engine family.

RAM Aircraft offers well-regarded engine upgrades for both models. But even RAM-converted GTSIO-520s carry the higher overhaul economics of the geared architecture.

The reserve arithmetic:

	Cessna 340A	Cessna 421C
Engine type	TSIO-520 (×2)	GTSIO-520 (×2)
Engine TBO	1,600 hrs	1,200–1,600 hrs
Overhaul per engine	~$55,000–$65,000	~$90,000–$150,000+
Reserve per hour (engines)	~$75–$85/hr	~$130–$200/hr

Over 1,400 hours of operation, that engine reserve difference compounds to $75,000–$160,000 — before any mid-time work, prop overhauls, or unscheduled events. This is the core of the 340 vs 421 decision for most buyers.

What the Market Actually Charges

We tracked 506 Cessna 340 transactions and 332 Cessna 421 transactions over the past 18 months. Here is where prices actually clear.

Cessna 340 / 340A — 506 Transactions

Percentile	Price
25th percentile	$198,000
Median	$279,000
75th percentile	$339,000

Entry-level examples — high-time 1972–1975 original 340s — trade between $110,000 and $175,000, but typically carry deferred maintenance. The real market for sound, flyable 340As sits between $185,000 and $350,000, with low-time late-model examples pushing $400,000–$500,000.

Recent sales from our records:

1972 Cessna 340 (6,800 TT): $259,900
1977 Cessna 340A (3,907 TT): $315,000
1979 Cessna 340A (5,596 TT): $279,000
1980 Cessna 340A (2,750 TT): $290,000
1981 Cessna 340A (2,905 TT): $475,000
1982 Cessna 340A (4,676 TT): $495,000

See the Cessna 340A price guide on Sprinkle →

Cessna 421 / 421C — 332 Transactions

Percentile	Price
25th percentile	$275,000
Median	$370,000
75th percentile	$489,000

Early 421Bs trade as low as $60,000–$110,000, but these are typically run-out examples — an engine-run-out 421 is an expensive problem to solve. Usable 421Cs start around $260,000–$340,000, with the market sweet spot between $335,000 and $530,000.

Recent sales from our records:

1976 Cessna 421C (9,095 TT): $399,000
1977 Cessna 421C (4,805 TT): $335,000
1979 Cessna 421C (5,850 TT): $634,000
1980 Cessna 421C (6,388 TT): $560,000
1981 Cessna 421C (6,200 TT): $399,000
1982 Cessna 421C (4,915 TT): $499,000

See the Cessna 421C price guide on Sprinkle →

The median price gap: $91,000 in favour of the 340. At the 75th percentile, that gap widens to $150,000.

Cabin and Capacity: Where the 421 Wins Clearly

The 421 has a meaningfully wider cabin — approximately 55 inches across versus the 340's 50 inches. Those five inches matter on a four-hour leg. The 421 can also carry up to eight passengers versus six in the 340.

Both aircraft maintain a cabin altitude of approximately 8,000 ft at FL250 — a genuinely comfortable environment for a full day of flying. Both are proper cabin-class aircraft, not just pressurised conversions.

The 421's geared engines deliver a noticeably quieter cabin. Prop tips turning at lower speeds produce less acoustic energy. Passengers who aren't aviation enthusiasts will notice the difference, and on a busy charter or executive transport operation, that matters.

For a pilot who regularly carries 5–7 passengers on 2–4 hour legs, the 421 offers a genuinely superior environment. For a pilot flying solo or with one or two passengers, the 340's cabin is entirely adequate and the premium is difficult to justify.

Operating Costs

Both aircraft burn 28–34 gallons per hour total, varying by power setting and altitude. At $6/gal, that is roughly $170–$200/hr in fuel alone.

Total all-in operating costs (fuel, maintenance, reserves, insurance) for a well-maintained owner-flown example:

Cessna 340A: $450–$600/hr
Cessna 421C: $550–$750/hr, and higher when engines are approaching TBO

Insurance rates also differ: the 421C commands higher premiums due to its higher hull values and its reputation for punishing poor technique.

Which One Should You Buy?

Buy the Cessna 340A if:

You typically carry 2–4 passengers
You want lower engine reserves and more forgiving engine management
Your budget sits between $200,000 and $380,000
You're transitioning from unpressurised twins
You'd rather spend the savings on avionics or a fresh engine reserve fund

Buy the Cessna 421C if:

You regularly carry 5–7 passengers and cabin space genuinely matters
You want 10–20 extra knots true airspeed at altitude
You have a professional A&P familiar with Continental GTSIO-520s
You're comfortable budgeting honestly for geared engine overhauls
Your budget sits between $340,000 and $550,000 for a sound example

There is also a third option worth considering: the Cessna 414 Chancellor sits between these two aircraft — pressurised, TSIO-520 engines (like the 340), wider cabin than the 340, and seating for 6–7. If you are genuinely torn between the 340 and 421, the 414 may resolve the decision.

Browse all pressurised Cessnas on Sprinkle →

Pre-Purchase: What You Must Check

On any Cessna 340: Inspect for corrosion in the wing spars and check fuel bladder condition. Pressurisation fatigue cycles create cumulative airframe stress — get a shop that knows these aircraft specifically. Fuel leaks from ageing bladders are common and not cheap to address.

On any Cessna 421: Engine time since overhaul is the most important number on the spec sheet. Borescope all cylinders and inspect the gearboxes specifically. Look for case cracks — they are a known risk on GTSIO-520s that have been run rich of peak. Do not buy on the cheap with run-out engines unless you have fully budgeted for both overhauls.

For either aircraft, budget a minimum $5,000–$10,000 for a pre-purchase inspection from a pressurised Cessna specialist. It is the best money you will spend.

The Verdict

The Cessna 340A is the more sensible purchase for most owner-pilots. It is capable, reasonably economical to operate, available in volume (our database has 17 active buyer alerts on 340 aircraft alone), and delivers genuine pressurised twin performance at a median price $91,000 below the 421.

The 421C Golden Eagle earns its premium if you genuinely need the cabin volume, the extra speed, or the passenger comfort of the geared engines. Its GTSIO-520s are a known quantity with a healthy support network. Budget for them properly and the 421 is a magnificent aircraft. Buy one run-out on the cheap and you will learn an expensive lesson.

Both aircraft have active, liquid markets. Neither will be difficult to resell if maintained well.

See all Cessna 421 Golden Eagle listings on Sprinkle →

Read our Cessna 421 ownership costs deep-dive →