The E series cams have the same base circle as a stock cam. Lifters (followers) and push rods can be re-used.
To swap the roller followers, you need to remove the heads. BUT, for a cam change, you can pull them up and hold them with a binder clip.
You'll need to remove valve covers, intake manifold, water pump, and front cover.
Be sure to drain the block well, or you'll get water in the
oil pan.