If you're looking for ratings from newish cars, try cars.com. They actually show what engines were/are available, and show the horsepower ratings for them. Plus I started a similar thread like this in the off-topic section.
1999 Chevrolet Camaro SS (PC'd)
1994 Chevrolet Beretta Z26 Q4 (W41 M90'd)
2004 Chevrolet Silverado 2500 (4WD)
My wife's cars:
1971 Dodge Charger SE (stock and original 383 auto)
2004 Subaru Impreza WRX (kid-hauler)