Torque converter size

Get a converter that is built for YOUR APPLICATION by a quality builder of performance converters. These builders will ask you a lot of questions to ensure that your get what is best for your combination. If you go to any of their websites, you typically will see an information sheet they want you to fill out. Any mis-information you give them will not be to your benefit. Also, just because the converter in my car is doing what it was intended to do, doesn't mean it would perform worth a damn in yours.
Don't let price be your only guide as you will only get what you pay for. Buy directly from the converter builder. Auto parts outlets that sell performance converters have staff that mean well, but usually lack the knowledge to get you the right converter. Avoid used converters.