sum ppl say frankenstein sum say hybrid. but its a mix of 2 different engines from the same engine class. like the lsvtec swap b18b or b18a bottom end with a b16 or b18c1 or b18c5 head. then theres the crvtec b20 bottom end with a b16 or b18c1 or b18c5 head. then theres the poor man type r with a gs-r bottom end and b16 head. then last but not least a k24 bottom end with a k20 head