James Dean is partially correct but not completely. The Z/28 was actually rated at 290hp and 290 ft lbs of torque but actually made about 325hp; more than the SS 350 which made 295hp. The SS 350 however made a lot more torque and these cars had about equal 1/4 mile times.
The Z/28s had very high revving engines that weren't ideal for street use. They had a 302 small block Chevy that was formed by combining a 327 block with a 283 crank, and had a big 780 carburetor, high compression, etc. They didn't start to make power til' well up into the rev range compared to the 350 which made strong low end torque and good mid range power which is ideal for a street performance car.
The Z/28 was only available with that engine, but the SS cars came standard with the 295hp 350 and had 3 optional 396 big blocks. I would rather have an SS 396 4-speed over a Z/28 but I would take a Z/28 over an SS 350 for the "image" and rarity. The power band is just different on the Z/28...it won't slam you back into the seat as soon as you hit the throttle but later after it gets to a higher rpm. Basically the Z/28 will start to shine as soon as the SS 350 starts to lose power in the rev range. It's a good lesson for a car enthusiast of how 2 engines with entirely different power bands can result in close to equal acceleration. The 396 however will beat both due to its shear size advantage.
