Cadillac has a history of daring engine choices: historic V-16s, massive 500-cubic-inch V-8 engines, and even an engine that featured cylinder deactivation 20 years before anyone else used it. Of course, nobody used the V-8-6-4's kind of cylinder deactivation for 20 years primarily because it didn't exactly work in 1981. What did work, though, was the revolutionary powerplant that Caddy introduced in 1991.
Part of what made the Northstar revolutionary was that it was designed as a high-revving, high-output V-8 engine from the outset. Shortly before the Northstar's introduction, some of its features -- like cross-bolted mains, dual-overhead-cams and an aluminum block -- were features rarely found on V-8 engines outside of racing applications. Many of its other features weren't necessarily racy, but they were only typically found on high-end engines like those produced by Ferrari, Lotus and Lamborghini. One of those was the engine's "even" firing order.
Cadillac numbered the Northstar's cylinders with odd numbers on the passenger side of the engine, and even numbers on the driver side. The firing order was 1-8-3-2-5-6-7-4. Notice that every other number is even or odd; that means that only one cylinder on each bank is firing at a time, and the firing order constantly switches back and forth. This "even" firing order makes for an engine that's naturally balanced and runs very smoothly at every rpm, and revs to high rpm without effort, vibration or drama. It's this smoothness that makes the even-fire arrangement preferred for performance-luxury applications like the Lamborghni Reventon, Ferrari Enzo and Cadillac Northstar 32-valve.