what is the size of ls1 rotors? And LT1 rotors, it looks like about 2 inches difference.

 

Try doing a search (here, on LS1.com or frrax.com). I don't remember exact specs off the top of my head, but yes it is a little under a 2" difference (the LS1 rotors are just under 12", while the LT1 units are about 10"). The upgrade is well worth it as it will look better and stop better.

 

I just got mine installed with my hawk hp plus pads. I love it. You better were your seatbelt or youll kiss the windshield.

 

LS1 is 12" in front. LT1 is 10.8" in front, 11.5" in rear.

 

Are you sure on that? I definitely know the LS1 setup is slightly under 12" (either 11.8 or 11.9, can't remember specifically), and I thought the LT1 rotors were closer to 10.5".

 

LS1 OEM rotors: 11.9"front / 12.0"rear

 

^^^ Sounds good to me. I measured mine last month when I did my brakes, and that's about what I got.