These mounts will allow you to install an E30 M42 into an m42 with the stock m10 subframe. They require you use e28 535 mount rubber. These are made to work with the stock e21 5 speed driveshaft from an 83 320i. There were some variations with driveshaft length so they may or may not work with all of them. The stock m42 transmission bracket will bolt into an e21 but we also offer a fabrication option if you do not have one.