Installed a 3.4 engine in a grand am gt now the car sits lower and it'* sitting on 18 inch rims any suggestions on getting this back to stock.

Do you mean getting the front end to sit at stock height because of the heavier engine? Install bigger springs up front. You might be able to use springs from a Grand Am that came with a V6 and use them. But, I'm only hypothesizing that idea.