I respectfully disagree with 03/04 cobras being better than LS1's...cuz when's the last time you've seen a 5,000 Cobra in decent condition? Yes stock for stock it's no doubt a Cobra will beat an LS1, but $ per HP I think hands down the LS1 would take it.
BTW I love LS1's and looked at plenty of them and my cousin has Cobra so i've been around both.