They are basically the same car; the main difference is trim packages and maybe the shocks.
Answer OK, stock for stock, an SS and a Z28 both have the SAME LS1 engine. This means it has the SAME performance. Now it has been proven that both dyno the same numbers. The ONLY advantage is the SS which has a better flowing exhaust, which in place will ONLY give it a 2-5hp advantage over the Z28 STOCK. Now if modding is your game then its only common sense that they will both react the same to the same mods! BUT for me, I went with the SS. LOOKS is what did it for me!
Answer Okay, first of all just because it's the same engine doesn't mean the same performance. But getting back to the question, the main difference is the horsepower and a little torque since i have had both. The Stock 2001 Z has 310hp and the SS has 325 hp both were increased 5 hp in 2001. The 15 more HP in the SS is from the forced air induction package offered by SLP which was stock on SS and optional on Z28. The SS also had a ram air type cowl induction hood which was also stock but an option on the Z28. I chose to keep my SS mainly because you don't see many and Z28 just don't get the looks a good SS does. Bottom line it's personal preference but the SS is faster.
Answer An SS Camaro does not dyno more than a Z28. The only SS that will dyno more than a Z28 is the SLP special edition SS. A regular stock SS Camaro is the same hp as a Z28. Manual Transmissions will dyno a little more than the automatic's so keep that in mind. An automatic Z28 or SS will dyno between 275-290 at the rear wheels while manual transmissions will dyno between 300-315 at the rear wheels. I have dyno sheets to prove this. Of course, Chevrolet never made an Automatic SS Camaro. The ram air hood on an SS will give a slight advantage but not until you are at a high rate of speed. Basically SS Camaro = Z28 Camaro with a new hood and new spoiler in a nutshell.