Big-block or small-block—which one is best? When this is the question, it matters whether you’re trying to win a drag race, or just a simple bar bet. You may be trying to come to a consensus to bulk up your gearhead knowledge or you may be building a period-correct street machine with a ton of power from an engine that matches the emblem on the fender. Do you already have a heavy favorite and want to back up an opinion, or are you a novice with an open mind and a thirst for hard facts? If you’re a student of domestic 20th-century V-8 engine architectures, you’ve come to the right place because we’ve got answers.
Engines in their simplest form are air pumps. The bigger the displacement of the pump, the greater the potential power; when all things are equal, the bigger the engine, the greater the power output. Unfortunately, in the argument of big-block vs. small-block, things aren’t equal, and our basic argument of “bigger is better” kind of hits the guardrail in a few places. First is the availability of aftermarket cylinder heads with high-flowing port shapes and large valves. The availability of these varies wildly for different engine families, when it exists at all. Moreover, the cost of parts may make building some engine brands cost-prohibitive at larger sizes and higher hp, so while you may crave a 455ci Oldsmobile big-block, for example, you may be better off with a new-era Chevy LS at half the cost per-hp. The 455ci Olds might have more cubes, but a 327ci (5.3-liter) LS is the better air pump of the two. Already, you’ve learned that the size of the air pump isn’t a marker for how well it pumps air.