how can you tell the c4 from a fmx trans

For those who don't want to down load a file: the C-4 is all aluminum ( bellhousing, main case, and tail housing) the FMX had an aluminum bell, iron main case and could have either an aluminum or iron tailhousing. C-4's pan is square and the FMX's is rectangular, with the long sides to the front and rear.Both had removeable bellhousings.
 
The number of bolts on the pan is the easiest way to tell what it is. If you've got long arms like me and don't mind getting your hands dirty, you can lay down next to the car and reach under and count the bolts without jacking the car up. C4 11 bolts, FMX 15 bolts, C6 17 bolts.