what exhaust manifolds do I have?

I was grabbing a set of disc brakes/ with a arms and decoded the vin to be a 69 Dart Custom w/a 383 2 barrel. So I pulled the exhaust manifolds and to make sure what I got I looked up casting numbers, I do not see them. The numbers are 3830905 8-15-74 drivers and 3830834. Now I'm not sure if it is a BB, I looked at the motor and the number on the drivers side is 4006730-31_. There were 2 race seats and no back seats, looked like it was a drag car before going to the pick a parts. I hope this is not a SB exhaust but it defenantly fit in the a body correctly. Any help would be appreciated.