For A expression with these types of outsized importance in motor vehicle tradition, "JDM" is an acronym for a reasonably uninteresting phrase: Japanese Domestic Industry. It refers to products built and meant for sale and use in Japan (i.e., not for export). This consists of every little thing from automobiles https://elevemotors.com/product/ford-mustang-gt-15-17-oem-engine-w-automatic-transmission-swap-assy-5-0l-v8-62k/