i know you need the motor but what other parts are needed for the swap i have an 2000 z24 cavalier and i need to what is all needed to put the eco in my car do i have to change the wiring harness and also will header fit the ecotec from my ld9 and what about my underdrive pulley will it fit the ecotec please help

for the swap... search

for the pulley and headers... if you look at any site for parts they list them seperate and have different part numbers for a reason, common scene should tell you they wont fit an eco. Its an entirely different engine. The only engine parts that will work is a cat back exhaust (cause it for the car not the motor) and lower motor mount and I think thats about it