What size will I be with 450cc implants, height 5'8 and weight 170lbs?

Thank you for sharing your question and photograph.  It appears that you have implants already placed and that your natural breast tissue has sagged over them.  Unfortunately there is little ability to predict a cup size after a lift or augmentation, as too many variables exist and it is better to focus on the specific result your are trying to achieve.  Be sure to see a series of ASPS board certified plastic surgeons in consultation to discuss the best implant size and lift needed.  Hope this helps.

It appears you have
implants, which are high on your chest wall and your breast tissue has fallen
down.  You will need a breast lift and the
technique I recommend is The Bellesoma Method. 
This will reshape your breast tissue creating upper pole fullness
without implants, elevate them higher on the chest wall and more medial to
increase your cleavage.  Vertical scars
are avoided, nipple sensation and the ability to breast feed are maintained, if
not injured during your previous surgery. 
Best Wishes,Gary Horndeski, M.D.

Dear Happiness 2018it is hard to predict breast size based only on implant size. Breast implant type and sizing selection is a complicated process and requires a detailed consultation that includes a discussion of your goals, a detailed examination, and a lengthy discussion. But the decision will always start and end with the patient. When it comes to sizing, we have all of our patients find 3 photos of their desired breast size. We ask for naked breast photos because clothing can obscure the true size (push up bras). Next, we consult with patients and go over the photos and take detailed breast measurements during a physical exam. Next, we using a sizing algorithm to determine a range of implants that will work based on the exam and the measurements.Lastly, during the operation, we use silicone sizers in the operating room to see how the size actually looks in the breast. We sit the patient up in the operating room, while asleep of course, and compare the sizer result with their desired look photos. If it is too small, we start the process over with a slightly larger implant. We don't stop until we get the perfect match.Of all of my breast augmentation patients, every one of them has been happy with their size due to this detailed and meticulous process. You don't want to invest time and money into a result that is either too big or too small.You should discuss your concerns with a board-certified plastic surgeon and make sure that your surgeon understands your goals.Daniel Barrett, MD
Certified, American Board of Plastic Surgery
Member, American Society of Plastic Surgery
Member, American Society of Aesthetic Plastic Surgery

Not sure if you already had the implants or not but the downward low position of the nipplese would be an indication for a breast lift for the best look.

Hi and welcome to our forum!
Unfortunately, it is impossible to predict cup size after  breast augmentation, especially since you have implants of unknown size presently. In addition, there is no standardization of cup sizes among bra manufacturers. One bra manufacturer's C may be another's D.
Wearing an implant externally in a bra may provide an idea of
size if you add in the size of your current implants. Consider bringing in "wish photos" to show your surgeon what
you desire. Adding rice to a bag from a measuring cup ( 1 cc = 1 ml) and
placed in your bra may determine fill volume after you add the number of cc of your present implants.  Breast dimension measurements are
essential as implants vary in width and projection. A  discussion
after thorough examination with your surgeon is required. The number of cc
is secondary....It's the "look" that should be of primary importance,
and that decision is up to you.
Of note, you appear to be demonstrating moderate sagging (ptosis) of the breasts. You may also consider a lift.
Seek a consultation with a board certified plastic surgeon.
Best wishes...