180 conv banner

C-180 Air Plains 300HP



Air Plains 300HP is approved for all Cessna 180 models, 1953 thru 1981.

To get better performance out of your Skywagon more horsepower is needed, plain and simple! The Cessna 180 Skywagon has it all: lots of ramp appeal, a great owner, and plenty of versatility. Why not get equipped with exceptional performance? Give your airplane the gift you have been dreaming for years... The exhillarating performance of 300 Horsepower. Cruise at 180 mph speeds and climb faster then a home-sick angel.

Once you feel the extra power available and the quality of our product the only thing you will wish for is that you had done the upgrade sooner. Air Plains sales team and technical support provides assistance before the purchase all the way to your flying.



IO 520 DFlying with the confidence that your aircraft can perform with no "hiccups" in and out of short fields at high density altitude is a feeling that every pilot should posses when it comes to your safety and the safety of your passengers. 

The IO-520-D engine generates 300 horsepower at an RPM of 2850, which is allowed for 5 minute intervals. On take off, at full throttle, 300 horsepower are available for five minutes, then a power change is made to bring the engine back to 285 horsepower (maximum continuous horsepower).

The IO-550-D engine generates 300 horsepower at 2700 rpm, and has no limitations. The basic difference between the IO-520 engine and the IO-550 engine is the stroke of the piston within the cylinder. The 550, being longer thus creating more cubic inches, and the 300 sustainable horsepower creates increased torque.

Powerplant IO-520-D IO-550-D
Manufacturer Continental Continental
Engine Model IO-520-D IO-550-D
Horsepower* 285 HP 300 HP
Maximum RPM 2850 rpm 2700 rpm
Time Between Overhauls 1900 hrs 1900 hrs
Fuel Consumption 15-16 GPH 17-18 GPH

* maximum continuous HP 


Learn more about Fuel Injection.

Fuel Injection or Carburetor  

While both fuel injection and carburetors have been used in the aircraft industry for decades the debate conintues on which is better. Cessna begin using fuel injected 470 and 520 cu. in. engines in 1960 in Cessna 210's and Cessna 182's. As different models of aircraft were added to production they were equipped with fuel injected engines. 

Cessna chose the Fuel Injected engines for horsepower and economy. Fuel injection provides even distribution of the fuel to all cylinders since a fuel nozzle is placed in each cylinder and fed individually with a line from the flow divider valve. In carbureted engines the fuel is introduced into the induction system at the carburetor venturi thru a single nozzle and then must make its way along a circuitous route to be introduced into the cylinder for combustion. The result of this circuitous route is that some cylinders get excessive amount of fuel and some get an insufficient amount of fuel.

Fuel injection allows the engine to perform to its full potential. A Fuel injected engine from Continental will produce 300 Hp for both the IO-520 and the IO-550 engine. An engine built as an O-520 or O-550 engine is de-rated and will produce significantly less horsepower. A side note to the fuel injected vs carbureted discussion, Continental has never produced an O-520 or O-550 engine. Continental engineering determined that the most efficient was to operate the high horsepower engine is with fuel injection.

Beside a more efficient engine, another big advantage to fuel injection is the potential of carburetor ice is eliminated. Carb ice is caused by rapid expansion of air as it passes thru the venturi in the carburetor which in itself cause’s the air temperature to decrease. That temperature drop is enhanced by atomization of the fuel which is introduced to the air at the same point. On engine’s that have the carburetor suspended from the induction system like the O-470 and O-520 engines the creation of carb ice can be a significant problem. On days of high humidity and 50° F frost may form on the induction system just above the carburetor. Cessna 180’s and 182’s are actually approved in the owner’s handbook to operate with partial carb heat during takeoff, climb and cruise.

So what does Air Plains do to a Cessna 180 or 182 to change it from a carbureted O-470 engine to a fuel injected 300 Hp engine? The airframe has some slight changes made to accommodate the change to fuel injection. The O-470 Engine is removed and replaced with 300 Hp IO-520 or IO-550 engine. Along with a new engine, Air Plains installs a new 3 blade propeller and propeller governor.

A fuel reservoir tank is added to provide a constant supply of fuel to engine in all attitudes. This fuel reservoir tank is installed in every Cessna single engine aircraft that has fuel injection installed. These would include restart 172’s, 182’s and 206’s.

Instead of beating on the firewall with a hammer to provide clearance for the high capacity oil pump and the engine driven fuel pump, Air Plains installs a small relief panel in the firewall. An electric fuel pump is added to the aircraft which aids starting and serves as a backup to the engine fuel pump. The result is a smooth running, fuel efficient engine system that is designed to give many years of safe operation. There are no excuses and no compromises with a fuel injected engine.



All propellers have been matched to provide the best combination of airframe and powerplant.

  D3A34C401 MT
Manufacturer McCauley MT Propeller
Model 401/90DFA-10 MTV-9-D
Engine Model IO-520-D | IO-550-D IO-550-D 
Blades 3 3
Diameter Max. 80 80
Diameter Min. 78  
Pitch Range 13.2-31  




The Air Plains 300 HP offers substantially increased climb and cruise performance.

APS 300 HP Performance
IO-520-D IO-550-D
Cruise Airspeed 175-180 mph 180-185 mph
Rate of Climb (S.L) 1400-1500 fpm 1700-1800 fpm
Service Ceiling 24,000 feet 24,000 feet



Air Plains 300HP is approved for all Cessna 180 models, 1953 thru 1981. The installation can be accomplish two ways, by Air Plains or by your local mechanic.

Installation of both engines are exactly the same, the only difference being the engine that is installed. The 300 horse installation involves the addition of fuel injection to the Cessna 180, which requires a modification to the stock gravity fed fuel system. The system installed is similar to the one used in the Cessna 185, Cessna 206 and Cessna 210. Modifications in the fuel compartment are minimal, involving a change to the engine mount, clearance gained at the firewall, and the remainder of the fuel injection system installed. The installation does not require any cowling modifications on most models. The only noticeable change is the addition of the 3 blade propeller and polished spinner.

Air Plains 300 horsepower engine upgrade design and installation have been developed from our experience in modifying and maintaining other Cessna aircraft at our facilities for more than a quarter of a century. Whether installed here at our facilities, or shipped to your local shop for installation, our Air Plains engine conversions has been developed to be delivered as a complete kit. Our standardized kit, installation instructions, blueprints, and continued airworthiness manual, safeguard the procedures and standards for installation and maintenance of your new conversion... no matter where you choose to have your conversion installed.

Kit Accessories

Kit Accessories

Kitting on the Skywagon Air Plains 300 HP changes slightly between models to accommodate changes in the original airframe design.

  • Engine Mount Modification
  • Baffle and exhaust Kit
  • New Alternator (if generator is present)
  • Air Plains PMA Parts
  • Hoses
  • Switches
  • Electric Fuel Pump
  • Manifold pressure and fuel flow gauge 
  • New Propeller Governor
  • Propeller and Spinner Assembly
  • Throttle and Mixture cables
  • Engine isolator mounts (four)
  • Fuel Reservoir Tank
  • STC Authorization, Drawings, and Installation Instruction

All kit parts are manufactured at our facilities, where we maintain close control on fabrication and production. Parts are FAA-PMA approved in order to ensure that you will receive the best quality and most complete upgrade kit. 


callout top2

CALL 1.800.752.8481 or CONTACT US