It is normal for different parts to have different (year) engineering numbers in a transmission, hence the c6 and c8 numbers, which is 66 and 68 respectfully. The C6 transmission has the bell housing and main body all one unit, not two pieces like the c4. Being a 428 it should have a c6 type in it. So if you look at the trans and the bellhousing and main body are one unit, you have a c6. There should have been a tag on either a servo cover or the transmission pan with the info on the trans. You also can tell the transmissions by the shape and number of bolt holes in the transmission pan.
Check out this site:http://www.fordification.com/tech/transID-auto.htm
My 2 cts. Good Luck.
Check out this site:http://www.fordification.com/tech/transID-auto.htm
My 2 cts. Good Luck.
