Engine Options

All Corvairs are Horizontally opposed, air cooled, six cylinder, direct drive engines.They can be run on either 100LL fuel, or automotive fuel, with ethanol content up to 20%.

All engines have equal reliability, the increase in power is always from a displacement increase, the engine is doing the same work per cubic inch.

All engines 2,700-3,000 are based on using the Forged GM crankshaft, but can be optionally equipped with a Billet crankshaft.

The 3,300 engine always has a Billet Crankshaft. Engines 2,700-2,850 use GM cylinders, 3,000- 3,300 use purpose made cylinders. Engines 2,700-2,850 use GM connecting rods with the option of billet rods, 3,000- 3,300 use billet connecting rods. 

All HP ratings are at 3,100rpm. All engine can be run at 3,400 rpm continuous.

2,700cc 100HP

Standard Corvair Conversion engine, Most popular engine in previous years. Based on Sealed Power Pistons. Weighs 235 pounds, slightly lighter than an O-200 Continental or a Viking 130. If run on auto fuel, the engine requires a slight timing reduction and is rated at 95HP. Most economical engine to build.

2,775cc  105HP

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Upgrade to standard engine, Displacement increase by .060” overbore.  Built with Ross Pistons, which allow full power on automotive fuel. Weighs 230 pounds, weight reduction due to overbore on original GM cylinders. Significant power and durability increase for modest cost increase.

2,850cc    110HP.

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  Displacement increase by .105” overbore. Maximum displacement increase with “bolt on” parts, (Larger displacements require machine work to the cases and heads)  Built with Ross Pistons, which allow full power on automotive fuel. Weighs 228 pounds, weight reduction due to overbore on original GM cylinders. Strong power increase with modest cost increase.

3,000cc  120HP

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Displacement increase by .186” overbore. Engine requires machine work to engine cases and heads, done at SPA. Significant ’seat of the pants’ power increase over base engine. Built with Ross Pistons, which allow full power on automotive fuel. Weighs 228 pounds, weight reduction due to specifically made cylinders.

3,300cc  125+HP

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Displacement increase by .186” overbore and a new billet crankshaft with .312” stroke increase.  Requires machine work to heads, engine cases and cam, done at SPA. Built with Ross Pistons, which allow full power on automotive fuel. Weighs 225 pounds, weight reduction due to billet crank and specifically made cylinders. Most powerful engine available, has a very wide flat power band.  Flagship engine most commonly built from “Engine In a Box” kit. Expensive in comparison to other Corvairs, but an excellent value compared to other high end engines like the UL350.

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