I had an 00 Z/28 that I added an LS6 intake/comp 918 springs,pushrods,221/221/560/560 "baby" cam/shifter/4.10's/12 bolt/ASP pulley/kooks LT headers,OR y-pipe and made 415/402 RWHP and ran 11.80's at 117.9 on a drag radial.They pretty amazing.
They pretty amazing..... considering they ditched the stupid chevrolet siamese port cylinder heads for a FORD design that they elongated and called their own. LS engines are only so great because their resemble Ford small blocks now. My brother was pretty pissed when my mild 306 was just as fast as his 350 built to snot. I could also hang with stock LS1's all day, in a car I paid no more than 3k for including all the upgrades. Upgraded LS1? it would beat me, but so what? Lots of money, far more design upgrades, I mean hell, the stock heads have just as big of runners as our aftermarkets do.