Will 400cc Implants Give Me a Full C or Small D Cup?

When ever you talk about bra sizes you have to realize it is not an exact science. Different manufactures have very different sizes and shapes so one manufacture may consider you a C and another manufacture will consider you a D. The cup size of a 32 C is very different than a C cup of a 38 bra. With all of this in mind, we still have a general idea of what you are asking.
With the information you have given in regards to height and weight and starting bra size it sounds like the 450 cc implants will be about right. One way to help confirm this is to try on some implants and see if this is close to the size you are looking for. No one can guarantee you to be a certain bra size but it sounds like you are real close.
Best Wishes
Dr. Peterson

The breast cup designation is often variable between bra manufacturers and depends likewise on chest wall inch measurements. With this in mind, prediction of outcome can be somewhat hazy. From your measurements the volume you quote sounds reasonable. Don't forget, there are different profile implants that may also have a bearing on cup outcomes. Discuss this with your surgeon.
As far as pre operative prediction, try placing the implants in a non padded bra with a T shirt or similar over. This gives a rough idea keeping in mind that externally, the implant will be approximately 50 cc smaller that the implant required for the augment when placed in the body. Perhaps even 75 cc if sub-muscular.
Hope this helps!