What is the difference between a long block and reg engine in hondas?

im particular about the 1992 honda prelude since i wanna swap it to my 91 accord is this possible ??? a 92 engine and transmission into a 91 honda accord. i recently seen the euro r engine but it costs alot but ive noticed long block engines are way cheaper why is that ? can i still make the long block as fast as the reg engine.