Depends on if your gonna make your own mounts and notch your own subframe or if your gonna use a kit. But a rough cost is around 10k. There are a couple kits out there for the LS1 conversion in the 240sx including: hinsonsupercars.com, daftinovations.com, and garry's kit. silviav8forum.com has alot of information that will help you out. Hope I could be of some help.