Go here for information diagrams and specific to you engine:
http://www.aa1car.com/library/chevy_firing_orders.htm
4 cyl:
front
1
2
3
4
Firing Order: 1-3-4-2
V6 front
1 - 2
3 - 4
5 - 6
2.1, 3.4, 3.6 liter, 173 c.i.d,
Firing order 1-2-3-4-5-6
231, 3800, 4.3 liter
Firing order
1-6-5-4-3-2
V8 front
1 - 2
3 - 4
5 - 6
7 - 8
265, 284, 307, 327, 400
396, 406, 427, 454
Firing order:
1-8-4-3-5-6-7-2
LS1 5.7, LS2 6.0, LS4 & LS6 5.3, LS7 7.0
Firing order:
1-8-7-2-6-5-4-3
Next time you pull all the plug wires off, make sure you diagram out where they go. It helps to mark the wires with a bit of tape with the number written on it.
Even easier is to pull and fix only one plug wire at a time.
If you get the wires off by a single count of one on the distributor, when you go to start the engine it will sound as if the entire world is ending.