The cylinder heads make the LS3, and there are a few factory options to add more power. As delivered, the LS3 castings have the L92 port. To review, the LS1 has the cathedral port that is tall and thin and worked great for the small-bore 5.7L engine. The next design was for L92-powered trucks, LS3 (Z06) Corvettes, and the new Camaro. The L92 intake port is 260 cc and resembles a big-block Chevy rectangular port. According to GM numbers, it flows 294/183 cfm at 0.500 lift.