In order of increasing capacity:
A standard replacement 3-row has 29 tubes per row, 87 tubes that are 1/2" for a total of 43.5 tube-inches. The flat-to-tube ratio is .87 for an effective 37.8 tube-ins.
A medium-tube high-efficiency (like the Modine X2K core) 2-row has 44 tubes per row, 88 tubes that are 1/2" for a total of 44 tube-inches. The flat-to-tube ratio is .87 for an effective 38.3 tube-ins.
A small-tube high-efficiency (like the GM HER or Modine "H" core) 3-row has 44 tubes per row, 132 tubes that are 3/8" for a total of 49.5 tube-inches. The flat-to-tube ratio is .83 for an effective 41.1 tube-ins.
A standard replacement 4-row has 29 tubes per row, 116 tubes that are 1/2" for a total of 58 tube-inches. The flat-to-tube ratio is .87 for an effective 50.5 tube-ins.
A single-row aluminum (F-body) has 39 tubes per row, 39 tubes that are 1-3/8" for a total of 53.6 tube-inches. The flat-to-tube ratio is .96 for an effective 51.5 tube-ins.
A original equipment Harrison 3-row has 40 tubes per row, 120 tubes that are 1/2" for a total of 60 tube-inches. The flat-to-tube ratio is .87 for an effective 52.2 tube-ins.
A small-tube high-efficiency 4-row has 44 tubes per row, 176 tubes that are 3/8" for a total of 66 tube-inches. The flat-to-tube ratio is .83 for an effective 54.8 tube-ins.
A large-tube high-efficiency (like the GDI/Proliance "VX" core) 3-row has 44 tubes per row, 132 tubes that are 5/8" for a total of 82.5 tube-inches. The flat-to-tube ratio is .9 for an effective 74.3 tube-ins.
A 1" double-row aluminum (like the Be-Cool, Griffin, Alumitech, Jegs, etc.) has 41 tubes per row, 82 tubes that are 1" for a total of 82 tube-inches. The flat-to-tube ratio is .94 for an effective 77.1 tube-ins.