Why does my surgeon say he can only go up to 350cc for my breast lift. Is this size going to be small? I'm 5'6, 150lbs size 34E

You need a formal evaluation by a licensed plastic surgeon and expert in breast lifts, revisions and augmentations to determine what is best for you and your goals.Breast lift surgery can improve a woman's breast shape by repositioning the breast mound at a higher position on the chest and then centering the nipple and areola on the breast itself. If there is enough breast tissue, I can perform a highly aesthetic mastopexy without the addition of further volume by internally rearranging the breast tissue and removing excess skin. If more volume is needed, especially in the upper portion of the breasts, we will discuss the possibility of fat grafting or silicone gel implant placement. The type of incision required for this surgery (circumareolar, “lollipop” or “anchor”) and the lifespan of the lift depends on each patient’s condition, breast tissue, genetics, weight and hormonal fluctuations, and desired results.
Augmentation with mastopexy is a challenging surgery that requires significant experience to create a shape that is youthful, natural, and proportionate to the body, while managing the native tissue as well as fat grafts or implants. When performed properly, it can result in a dramatic improvement to a woman’s breast appearance.
I suggest consulting with a board-certified plastic surgeon and expert in Breast Lifts. - Dr. Cohen

Thank you for the good question.  Some general thoughts regarding this combination procedure may be helpful to you:
 Generally speaking, patients undergoing the breast augmentation/lifting combination operation should understand that it is significantly more complex than breast augmentation surgery only and that it is associated with a significantly higher risk of complications and need for additional surgery. 
Also, patients undergoing the combination breast augmentation/lifting surgery should understand that there are limits as to how large of an outcome can be achieved, given that breast lifting surgery does involve breast skin removal. On the other hand, breast augmentation surgery is expanding the breast skin “envelope” while breast lifting is (by definition) tightening up the breast skin envelope. These 2 forces are counteracting each other. 
Therefore, it becomes important to remove the appropriate amount of breast skin and to use the appropriate size/profile of breast implants to balance these 2 forces appropriately and to allow for achievement of the patient's goals while minimizing risks of complications. 
In my practice, "tailor tacking" is an important part of the mastopexy and mastopexy/augmentation procedure. It involves TEMPORARY  closure of the skin (for example with temporary skin staples)  to double check the amount of skin that is to be excised during the procedure. This maneuver is done to ensure that enough skin, but not too much, is removed. On the one hand, it is important that enough skin be removed to achieve the aesthetic breast lifting results the patient is looking for; on the other hand, is important not to move too much skin creating tension upon closure and potential wide scars.
 
Also, generally speaking, the best online advice I can give to ladies who are considering breast augmentation/lifting surgery (regarding breast implant size/profile selection) is:
1. Concentrate on choosing your plastic surgeon carefully. Concentrate on appropriate training, certification, and the ability of the plastic surgeon to achieve the results you are looking for. Ask to see lots of examples of his/her work. Seek additional consultations if you are in doubt.
2. Again, have a full discussion and communication regarding your desired goals with your plastic surgeon. This communication will be critical in determining which operation and/or breast implant size/type/profile will most likely help achieve your goals.
In my practice, the use of photographs of “goal” pictures (and breasts that are too big or too small) is very helpful. I have found that the use of words such as “natural breasts” or "C or D cup" etc means different things to different people and therefore prove unhelpful.
Also, as you know, cup size varies depending on who makes the bra; therefore, discussing desired cup size may also be inaccurate. The use of computer imaging may be very helpful during this communication phase.
3. Once you feel you have communicated your goals clearly, allow your plastic surgeon to use his/her years of experience/judgment to choose the breast implant size/profile that will best meet your goals. Again, in my practice, this decision is usually made during surgery. The use of temporary intraoperative sizers with the patient in the upright position makes selection of the best breast implant size/profile relatively easy.
Best wishes.