How can I chop the top

$10 in sawzall blades should do it.

Then you'll need to cut out sections, and re weld. Also you will need to cut the door frames. Then add a custom windshield and door glass. Maybe a new seat frame and driver seat, as you will need to lower the seat so you can sit in it. Ask a body shop, probably a couple thousand due to the labor involved, welding, fit, welding, paint and sourcing non OEM parts.

This all depends on if you want a redneck job or a custom show truck. ;)