Merging Drawing into One

You will need a very large canvas to accomodate multiple 8.5 x 11 drawings.  Hi-resolution will add even more to the file size so I hope you have plenty of computer memory. 

Do you mean it is the same image repeated on multiple paper  in which case :

If they are drawn with black ink/pencil on white paper, try putting each on a separate layer and then set the layer blend mode of all except the bottom layer to multiply. Then align as required

If the paper is not pure white you may need to use curves to lighten it.

or do you mean parts of a large image each drawn on separate paper in which case:

Create a large canvas:

Use File place to place each image on the canvas and then move/transform as required to align them next to each other

Dave