350

depending on what kind of power its gonna make, ya may be able to keep the stock rearend, but if its gonna be built id go with a 12 bolt or a 9in. -Trans. id either run a th-350 or a th-400.

What rear end does it have? I still use the 8.5 10-bolt in my car and have had no issues, unless you use a power adder stock should be enough. I would get an OD trans if possible like the 700-r4. It makes cruising much more enjoyable and helps on gas a bit too.