There are several methods of adapting a GM TH400 to a big-block Ford, but the most practical for a track-oriented application is with an Ultrabell bellhousing from J.W. Performance Transmissions. It features the Ford bellhousing bolt pattern on one side, and attaches to the TH400's front cover on the other side. Of course, this requires cutting off the factory bellhousing using a template included in the J.W. kit. With the measurements scribed on the case, the old bellhousing was hacked off with a plasma cutter. Afterward, final shaping was performed using a hand file to ensure a close fit to the trans case.