Next time number each lead before you remove it and no. the dissy cap as well
The firing order, which should be cast into the intake manifold, for the chevy small block V8 is 1-8-4-3-6-5-7-2. The firing order is the numerical sequence in which the spark plugs are fired. The insertion position of each spark plug wire around the circumference of the distributor cap can be found according to a clock face. The insertion sequence determines the firing order. The firing order is followed clockwise around the distributor cap starting from the 6:30 position with the 6:30 position being the number one cylinder spark plug wire.
On classic chevy small block engines that use ignition breaker points instead of electronic ignitions, the number one cylinder is the one immediately clockwise of the small metal sash cover on the distributor cap. The firing order starts here. There is no sash cover on the distributor cap for GM HEI electronic ignitions, and the firing order is the same, but starting at the 5:30 position.
The firing order makes sense if you know how the cylinders are numbered. The number one cylinder is the front most on the drivers side and 2 being the front most on the passenger side. From front to back, the cylinders are odd numbered on the drivers side, and even numbered on the passenger side.
See the diagram; Click to open a printable larger image in a new window. The firing order starts with the number one cylinder. We would connect the number one spark plug wire to the distributor cap terminal in the 6:30 position.
Since the next cylinder in the firing order is 8 (passenger side rear), we connect the number 8 spark plug wire to the next distributor cap terminal (approximately 7:30 position) in the clockwise direction from number one. You need to be sure you continue the firing order in the clockwise direction around the chevy small block distributor cap from the last installed spark plug wire. Setting the rest of the firing order is just a matter of repetition. Be sure to count the spark plugs from front to back on each side of the motor to identify the correct cylinder number in the firing order.