Hi Ive got a 2000 automatic C5. I added ls6 cam ls6 intake, black wing cold air, and holowed out the cats. I just had my car dyno tuned and it only put down 319RWHP!. On all the post I read I thought it would put down 345RWHP?

The only thing I might have done differently than people on this board was not to put down a catback, because I also read that the stock corvette cat back flows real well on cat back gains are minimal, I guess I was wrong.

Now I'm thinking about getting and aftermarket cat back or Zo6 cat back but am worried it might mees up the dyno tune I had?

Anyway how much RWHP would I gain from a aftermarket cat back or Z06 cat back( do z06 catbacks put down the same gains)?

Any comments would be greatlyu appreciated THANKS!

First, I'd replace the cats and see if that helps: removing the cats on stock or lightly modded LS1s often hurts performance: the stock camand tuning are designed to need th eback pressure.

Second, a good aftermarket cat back willgive you a bit more power. I would not go with a C5ZO6 exhaust -- its better than the standard model's but there are aftermarket ones that are even better.

Finally, your power gain is slightly disappointing, but there is no way you should really expect 345 RWHP on an automatic with those mods, that cam, and stock heads: simply adding together all the Hp additions that people claim usually gets you about twice what you will really get. I would have expected 325ish though.