Regular text messages have a max length of 255 characters. MMS can have up to 1000 characters. Depending on your phone, and the phone/carrier of the person recieving your message, longer messages may be truncated, or they may be split up and sent as multiple "extended" messages.
It does not split on exceeding the stipulated length of the message but just abruptly truncates. I do have enough text message credits in my plan and hence splitting should be a most desirable option right?
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