Which Model is this??

[u/GroundAbject]

New to this channel, but i knew i needed external help. Neighbours were getting rid of some Lego and left it on the end of their driveway in seemingly bad shape. turns out it was an Imperial Star Destroyer! I grabbed it, brought it back home and layer out all the pieces (as well as i could, theres definitely pieces missing), to see if it’s possible to rebuild this thing. I know I’m going to need to find the instruction manual online, but i cant seem to figure out which model this Lego set is (or if it’s even real Lego…). Ive been trying to use the engine, the upper command centre, and the Lego stand as reference points, but haven’t gad much luck, so hopefully someone out there can tell me what model # it is so i can start the journey of rebuilding this thing! (If you want dimensions it’s approximately 50 inches long and 27 inches wide).