Motors, like music, were much simpler in the '60s. When Chevrolet unveiled the big-block V-8 back in 1965, the only decision in a record store was whether to buy the single or the entire album on vinyl. Since then, we've witnessed the advent of four-track, eight-track, quad-sound, laser discs, and cassettes; today we've got CDs, DVDs, and digital audio files on the Internet. Like rock 'n' roll, the big-block Chevy V-8 has been transformed by evolution and revolution.

For more than 25 years, Chevy's big-block V-8 was a rock of stability. It didn't take months of research to become a Rat-motor expert because virtually everything was interchangeable. As long as you could remember the difference between heavy-duty truck and passenger-car blocks, and recall which crankshafts needed external counterweights, you could pass as an authority.

In those innocent days, confirmed Chevy fanatics could make fun of the Ford guys who had to deal with incomprehensible parts combinations. Ford parts seemed to change almost daily, and a block built in August sometimes couldn't be used with a crank forged in October of the same year. Well, what goes around comes around: Now with three generations of big-blocks in circulation--Mark IV, GEN V, and GEN VI--Chevy stalwarts have to go through the same mental gymnastics. A degree in big-block genealogy is now a prerequisite before mixing and matching heads, blocks, camshafts, and cranks.