660cc's Silicone under the muscle implants to get a full DD. Is it possible for me to get these implants for my height/weight?

It is very difficult without assessing you in person to know if the implant size you mentioned would be appropriate for you. Keep in mind that implant size selection not only depends on your personal preference, but it also depends on your unique measurements. A thorough consultation with a board certified plastic surgeon will allow you to communicate what your desired result is and will inform you as to what is possible to achieve your goals. We have a device called the Vectra 3D imaging system that shows you what you will look like with any implant. Our patients are very happy with the choice of implant they make when using this system. To learn more about how to choose the right size implant, you can read "A Comprehensive Guide to Breast Augmentation."

Hello and thank you for your question.  The
best advice you can receive is from an in-person consultation.  This will depend on your individual breast measurements.  660cc is a large implant and in some patients may be too large for their skin envelope.  The size,
profile, and shape of the implant is based on your desired breast
size/shape, your chest wall measurements, and soft tissue quality. 
This decision should be based on a detailed discussion with
equal input from both you and your surgeon.   Make sure you
specifically look at before and after pictures of real patients who have
had this surgery performed by your surgeon and evaluate their
results.   The most important aspect is to find a surgeon you are
comfortable with. I recommend that you seek consultation with a qualified
board-certified plastic surgeon who can evaluate you in person.
Best wishes and good luck.
Richard G. Reish, M.D.
Harvard-trained plastic surgeon

Patients often think in terms of cup size when considering
augmentation. Unfortunately, devices are sized in terms of milliliters (cc) of
volume. This can lead to some confusion when sizing. Additionally, it is
important to remember that cup size itself is not standardized with variations
from one manufacturer to another. Unfortunately, as many women can attest their
cup size in an industry leader such as VS is not necessarily transferable to
another brand.
Another point which is often under appreciated is that of
anatomy and starting point. Any implant will add volume to the volume which is
already present. The implant is additive. A particular volume will not
necessarily confer the same cup size to different patients (often times it will
not even confer the same cup size to different breasts in the same
individual...remember they are "sisters" not
"twins"). 
A general rule of thumb is that 125cc can represent somewhere
between 1/2 to a full cup size increase. Smaller volume differentials (25-50cc)
are typically less consequential representing a volume change of less than
a shot glass. However, I have found these numbers, at least anecdotally, to be
of little help. Patients often present with notions/goals which do not
correlate with these sorts of sterile volumetric assessments.
When sizing patients, there are a number of useful tools
including:
-3D imaging (has the added benefit of offering a volumetric
analysis of the pre-operative breast)
-Breast sizers (rice bags)
-Goal photos
I also recommend that patients commit to a particular look
rather than a cup size. Once a patient settles on a look that pleases them the
overall cup size increase becomes less relevant.With regards to your specific question, it is difficult to offer any firm advice without any photos or in-person assessment. If you do, in fact have a smaller frame with a paucity of tissue, a 600 cc device may be tight leading to a sub-optimal outcome.
As always, discuss your concerns with a board certified plastic
surgeon.