Speaking of assembly line engines - in '65 two of my older brothers ordered new GT Mustang with the 225HP 4 barrel engines. One coupe and one convertible. The coupe was always just a little faster (probably a bit lighter too). Over the years, the coupe got sold and the convertible went up on blocks until a complete restoration about 10 years ago. When they tore the engine down, it had 7 "eyebrow" pistons and 1 flat piston from the lower compression 195HP 289. That explained a lot!
