How to remove windshield?

I agree with cuttin the old seal! You're going to find out that these old windows delaminated and fog at the bottom from the old adhesives used to bond them together! Any excess horsing around to try to get it out of the old seal could hasten the delaminatuin process and render the window no better than the one you need to replace! If you must try to save the old gasket, you may find that it is bonded to the window, so you better take along a spray bottle of soapy water, and a guitar string or plastic putty knife to help unbond the runner from the glass!!

You may also find that there is a plastic piece of trim inside the window where it meets the dash! Usually in tough shave from years of sunlight, this trim was color coded to match the interior color of the dash frame! Save it if it's in good shape, they're hard to find in any color!!