I have a drg. its base Units  are imperial, however it is dimensioned in metric.It is a Civil Roads Drg so it has a vertical 1/100 and horizontal 1/400 scale.I am looking to convert it to 1/1 metric.any ideas 

You should look at making a block out of the entire drawing and inserting it into a new drawing.  AutoCAD allows you to scale a block at insertion in both x and y directions.  After you have positioned the block, explode it.