Any traditional LA bellhousing will also fit the Magnum blocks. If you are looking for a cheap trans option, You can use aluminum overdrive 4 speed transmissions in Dodge trucks and vans up until 1987. They have the longer tailshaft housing, but BigBlockDart.com shows how to deal with that. PickNPull still has them coming through every now and then. You will still need to deal with flywheel balance if your Magnum is a 360. Good luck!