The two basic types of rods are I-beam and H-beam. Some say H-beams look heavier, but can end up being lighter than some I-beam designs, but not in every case. Which rod design is better is an ongoing debate, and we’re not taking sides, just showing off what’s typically offered. The designation comes from when you cut the beam: the end shapes a letter. X-beam and A-beam rods also exist, but are not common in the high-performance Chevy world.