The firing order on a 1985 Oldsmobile Cutlass with a 5.0 V8 is 1-8-4-3-6-5-7-2. The firing order cannot be changed in any way. The distributor turns clockwise so this is the direction in which the spark plug wires must be installed. The first order of business is to locate the number 1 cylinder terminal on the distributor. If you already removed the distributor, the initial timing must be set before starting.
Remove the distributor cap using a flat head screwdriver to unlock the screws on the cap. Bump the engine over until the rotor is pointing close to the number 1 cylinder. The number 1 cylinder will be the first cylinder closest to the radiator on the driver's side of the engine. The cylinder numbering on an Oldsmobile has all the odd cylinders (1, 3, 5 and 7, in that order, front to back) on the driver's side and the even numbers (2, 4, 6 and 8, in that order, front to back) on the passenger side.
Hold the distributor cap and install it slowly, paying attention to the closest terminal to the mark on the housing. Rotate the distributor so that the rotor is pointing directly at this terminal. This is the number 1 cylinder and the beginning of the firing order. Tighten the distributor enough to keep it from moving, using a wrench.
Install the distributor cap and lock the snaps into place with the screwdriver. Loosen the distributor hold-down bolt with a wrench and rotate the distributor counterclockwise to advance the spark 10 degrees. Tighten the hold-down bolt. This is the initial startup setting. Once started, the distributor can be fine-tuned. It should have 32 degrees max at 3,000 RPM.
Install all of the spark plug wires, starting with the number 1 cylinder and working clockwise around the distributor. The number 1 cylinder--the driver's side front cylinder--wire goes to the terminal used in Step 2 and to the driver's side front cylinder. The next terminal on the distributor goes to the number 8 cylinder--the second cylinder to fire in the firing order; this one is located closest to the firewall on the passenger side.
