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3390 Old Statenville Rd.

Valdosta, GA 31606


120 HP IFB
Spyder Corvair Conversion


We have been putting a lot of effort into the development of our 120 HP version of the Spyder Corvair Conversion Engine.   Our focus in the design of this engine has been to address some of the issues that arrive into designing a bigger engine yet allowing for ease of maintenance, parts availability, and reliability.   

The first production style engine has been built and delivered.  We are doing more testing and will be installing a 120 HP Spyder into the Saberwing as soon as our performance tests with the 100 HP engine are completed.   We plan to keep production to around 10 engines this year with current capabilities.  As we improve our facility we will be able to produce more.

What makes our  120 Corvair Conversion Spyder Engine deliver 120 HP? 

We approached this engine design by addressing a couple major factors in engine modifications.  We wanted to leave the case and heads in as-close-to stock condition and replace specific engine parts with new productionable parts.  There are only a couple ways to increase horsepower in an engine. One) you can increase discplacement through increasing piston/cylinder size/stroke.   Two) Improve a given engine size power through increasing compression ratio/timing and fuel system modifications.

We decided to increase the displacement of the engine by using the largest piston/cylinder arrangement that would fit in a stock case and heads and replace the crankshaft with one that has been stroked 0.250".   This change increases the colume of the engine from 2.7 liters to 3.1 Liters.   Our new crankshaft and prop hub design also allows us to advance the cam timing @four degrees to improve the torque the engine produces.   On propeller driven engines we gain more improvements in power by increasing torque since RPM is dictated by prop size.

Our Spyder 120 HP Corvair Conversion Engine has a brand new 4340 crankshaft that has been stroked .250".  It is forged, nitrided, counterbalanced, and gun drilled.   The counterbalances allow the engine to rotate more smoothly and more balanced.   Although it has more mass due to the counterbalances, the gun-drilling removes excess material and we end up with a crankshaft that only weights 2 ounces more than a stock one.

   New Stroked Crankshaft

The Pistons and Cylinders are brand new, forged, JEI pistons with full floating wrist pins.  They are lighter than stock pistons and have less drag due to an asymetric design.  The cylinders are also brand new, full finned cylinders with improved cooling area.

  New Cylinder with Piston

The Forged Connecting rods are also of a new design, incorporating the floating pin bushings and clearanced for the stroker crankshaft.  They are designed to handle higher horsepower applications.

New Forged Connecting Rod

After the 120 HP IFB Spyder engine is assembled it is mounted on our custom dynomometer and test stand to run for a few hours to check for leaks, power output, and general condition to insure a safe running engine to be delivered.

   Engine being pre-oiled and checked for oil flow through main/rod bearings before final closing.


Email or call us  (229)834-8996 if you have questions about the 120 HP Spyder Corvair Conversion Engine or would like to get in line to purchase one.