Question: how to tell the difference between a turbo 350 and a turbo 400?
Answer: Look at the transmission pans on both transmission. Both transmission pans have 13 bolts, but they have a different shape. The TH-350 uses a square pan, with one corner cut off. The TH-400 uses an oblong-shaped pan with one side having a "hump" in the pan and one side is curved while the other two sides are straight.