No mention at all about the HP/Torque Ratings.
Wel, at least you know they weren’t sacrificed.........
http://www.westport.com/news/2012/westport-announces-new-product-enhancements-on-flagship-hd15l-lng-engine-for-class-8-trucking
http://www1.eere.energy.gov/cleancities/pdfs/ngvtf10_natural_gas.pdf