I'm always apprehensive when I buy "custom fit" plug wires. But this set fit pretty well. The coil wire was slightly shorter, and the #8 wire was about 3" too long. In my opinion, the overmolded boots at both ends exceed OEM quality. The insulation is large, 8.5mm, compared to the stock diameter of 7.0mm. Due to the diameter of the insulation, expect to modify all of the plastic wire loom holders and the metal shrouds that cover the boots near the exhaust. This means more work, more frustration...but everyone that changes wires on a LT1 would only like to do it once. This is a small price to pay for the gain, as they are "Super Conductor" indeed. I measured the resistance of my old wires and this new set. An example: my old coil wire was just shy of 4,000 ohms....the new coil wire: 34 ohms. Huge difference!