The expression 'Mark IV' referred towards the motor's position given that the fourth evolution of a big displacement motor thought that dated every one of the way again on the 1950s. The differences between the initial 409 cubic inch major block (often known as the W-collection) ended up a lot https://impalaspareparts08516.webdesign96.com/36412012/60-40-chevy-bench-seat-fundamentals-explained