See prices below.
Please note, all prices are in US$

Propeller Speed Reduction Units (PSRU’s) are also part of the Firewall Forward product line. The CAMDRIVE 500+ PSRU, is designed to handle up to 700 hp.

The design and build up of this unit is the result of years of hands on experience dealing with PSRU’s by both Butler and Wilson. Bell Housings are designed to fit the Chevrolet V-8 blocks being used by many builders of the Fighter Escort Wings Mustang, Lancair IV and IVP, Express, Piaggio, replica warbirds, and others.

This gearbox, when matched to a GM engine, is an economical re-engine solution for owner operated and experimental category agricultural spray planes currently using 0-470 and IO520 engines. The fuel savings by using MOGAS instead of AVGAS makes conversion payback in months instead of years. Engine overhaul costs are a fraction of Continental and Lycoming engines. Firewall forward weights are within a few pounds. Some cowl mods may be necessary. Air conditioning is easily added. Contact us for information on complete firewall forward packages.

  • Stronger materials
  • Handles more power
  • Improved oiling system

– some parts are still available for older CAMDRIVE 500 PSRU’s. Note: Some parts are not interchangeable due to closer tolerances. Contact us for details.


Height 17.25 in.
Width 9.25 in.
Length 16.5 in.
Ratios 2.118:1 **
Weight 87 lbs.*
Offset 9 in.
Total weight 109 pounds (Includes PSRU, PTO, Governor Drive, Bell Housing, Belt, Coupler, all bolts, nuts, washers, and fittings, Prop Flange and Nut)
*  approximate weight depending on accessories   


  • Helical cut gears mesh continuously for smooth power transfer, extended life, and quiet operation.
  • The gear case is cut from 7000 series aircraft grade aluminum billet stock by a CNC machine. Billet stock allows precise load carrying capability calculations not possible with castings. It reduces weight and provides maximum structural integrity to overcome gyroscopic precession forces.
  • Optional fail safe coupling absorbs torsional harmonics. The coupling provides both torsional damping as well as a fail safe connection to the PSRU. If the torsional material in the coupling were to fail, the coupling would still allow engine torque to be transmitted to the PSRU.
  • Lubrication is by dry sump system independent of the engine. Internal oil galleries eliminate the need for external oil lines.
  • The gears are cut from an extremely tough alloy developed for heavy equipment and therefore does not need to be heat treated. As a result, the possibility of tooth chipping is virtually eliminated.
  • The nose cone is in compression while the attachment studs are in tension.
  • The gear case is also in compression with studs in tension. Two of the studs carry through from the front plate to the block.
  • Two power take-off points on the rear of the case are driven by the output gear.
  • The output shaft is drilled for hydraulically controlled propellers.
  • Optional accessory drives (2)
  • Optional custom bell housing assures perfect alignment and has pads for forward engine mounts.

The CAMDRIVE 500+ Propeller Speed Reduction Unit is a key part of the power train for the Fighter Escort Wing’s Mustang.

9-inch offset 2.18:1 ratio



Governor mount, drive assembly, sprocket and belt


Power take-off
assembly, gearset, sprocket, shaft, and side guard


Failsafe torque coupling


Machined flywheel spacer

$295.00 – $995.00

Custom cast and machined bell housing adaptor (fits all Chevy small block V8 engines and others)


Forged M1 billet bell housing for extra strength