Big-block rods come in a variety of lengths, most of which are pictured here. There's also a 6.250-inch rod, which Probe uses in several of its 460 and 489 big-block builds.
1. This 6.135-inch is Probe's 5140 forged replacement for a stock-sized rod. At $180 per set, it's an affordable step up.
2. Rods measuring 6.385 inches are used in many big-blocks, especially the popular 540s.
3. This 6.535-inch 4340 H-beam rod is 0.400 inch longer than stock, so it requires a piston with a 0.400-inch-shorter compression height, or a tall-deck block.
4-5.A 6.700-inch rod is usually only found in a tall-deck motor; the 6.800-inch arm requires it.