Depends on what year Z28 you're referring to...
93-97 z28 camaro's have 275 stock horsepower at the crank, not RWH.
245 horsepower
285
200 wrhp stock
310 horsepower 325 horsepower
285 horse
Depends on what engine it has...
275 horsepower and 285 ft lbs of torque
305
275 to the flywheel
190 hp
The 350 V8 if I recall is rated at about 190.