From Verizon Text FAQ's
How many characters can I receive in my text messages?
Verizon Wireless can support up to 160 characters in all Text Messaging markets. If you have an EMS (Enhanced Messaging Services) capable device, messages up to 1000 characters may be supported. Please consult your device’s User Guide for details.
Different phones have applications that will 'break-up' longer messages into multiple messages. If your outgoing messages are not being split, it is probably because your phone does not support this function. The Verizon network only allows an incoming SMS (Short Message Service) text to be 160 characters. Anything longer will be truncated