Push rod help

I have got a 1999 olds mobile achieva it has 149,000 miles on it. It's got a 3100 v6. I just put head gaskets on the car I've got it all together but on thing the Push rods. 6 push rods are long. 6 push rods are shorter. I called the GM dealer. They said. The long push rods go to the exzost. Valves. The short ones go to the intake valves. But they couldn't tell me an order they would go in. Or. If the intake valves are on the left or right side. Please help me out. Thank'z alot.