Westport Receives Largest Non-Port Order to Date For Heavy Duty Fuel Systems

VANCOUVER, BRITISH COLUMBIA--(Marketwire - June 5, 2008) - Westport Innovations Inc. (TSX:WPT), a global leader in alternative fuel, low-emissions transportation technologies, announced today that HayDay Farms of Blythe, California has ordered 20 heavy duty liquefied natural gas (LNG) trucks featuring Westport's High Pressure Direct Injection (HPDI) technology. The HPDI technology will allow HayDay's new Kenworth T800 trucks to operate in regional haul applications with the same power and efficiency as a diesel engine and provide superior economic and environmental benefits by running natural gas.

"At over US$4 per gallon for diesel and the natural gas equivalent at approximately US$3 per gallon, purchasing LNG trucks delivering the same torque and efficiency just makes sense," said Dale Tyson, Vice President of HayDay Farms. "Running LNG trucks with Westport's HPDI technology can help reduce fuel costs and harmful emissions providing economic and environmental drivers in line with HayDay's core business values."

"Providing a highly efficient, low-emission Westport ISX G 15 litre engine with a comprehensive support program for customers like HayDay Farms gives Westport a distinct competitive advantage," stated Michael Gallagher, President & Chief Operating Officer of Westport Innovations. "The economic drivers in concert with environmental benefits for customers like HayDay Farms are now creating unprecedented interest in our new natural gas fuel systems for heavy duty trucks."

About HayDay Farms

Hayday Farms was founded in 1986 with the acquisition of Toshin Trading, Inc., a hay brokerage company located in Blythe, California. Along the way, the name was changed to reflect its core business. HayDay Farms focuses on producing quality feed for foreign and domestic dairy and beef cattle. Show and stock horses are also a market segment with alfalfa, timothy, oats, Bermuda hay and hay cubes made available to ranch stables and feed stores. In addition, the Company has created a show horse hay package consisting of small compressed hay bales of alfalfa and Bermuda hay. Additional information on HayDay Farms can be found on their website at www.haydayfarms.com.

About Westport's LNG System for Heavy Duty Trucks

Westport's liquefied natural gas (LNG) system for heavy duty class 8 trucks offers industry-leading emissions, including lower greenhouse gas emissions than comparable diesel engines, and allows trucking fleets to move to lower-cost, domestically available natural gas and/or biogas. Based on the industry-leading Cummins ISX diesel engine with cooled EGR, the LNG version of the engine offers the same horsepower, torque, and efficiency as the base diesel engine rating it is replacing. The Westport LNG system comprises LNG fuel tanks, proprietary Westport fuel injectors, cryogenic fuel pumps and associated electronic components to facilitate robust performance and reliable operation. The Westport LNG system is 2007 EPA and CARB certified to 0.8g/bhp-hr NOx and 0.01g/bhp-hr PM.

The Westport LNG system for North American markets is available with 400 and 450 horsepower ratings and up to 1,750 lb-ft torque for heavy-duty port, goods distribution and other commercial truck applications. LNG fuel tanks can be configured to suit customer range requirements. Trucks are eligible for federal tax credits in the United States and may be eligible for other state-specific emissions credits.

About Westport Innovations Inc.

Westport Innovations Inc. is a leading global supplier of proprietary solutions that allow engines to operate on clean-burning fuels such as compressed natural gas (CNG), liquefied natural gas (LNG), hydrogen and biofuels such as landfill gas. Cummins Westport Inc., Westport's joint venture with Cummins Inc., manufactures and sells the world's broadest range of low-emissions alternative fuel engines for commercial transportation applications such as trucks and buses. BTIC Westport Inc., Westport's joint venture with Beijing Tianhai Industry Co. Ltd., manufactures and sells LNG fuel tanks for vehicles.

Note: This document contains forward-looking statements about Westport's business, operations, technology development or the environment in which it operates, which are based on Westport's estimates, forecasts and projections. These statements are not guarantees of future performance and involve risks and uncertainties that are difficult to predict, or are beyond Westport's control. Consequently, readers should not place any undue reliance on such forward-looking statements. In addition, these forward-looking statements relate to the date on which they are made. Westport disclaims any intention or obligation to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise.