You are in the right forum. Stock trans but Modified engine.

The t98 will live just fine behind a big hp engine. A lot of people that put big engines in also want to be able to cruise down the highway. That is why you read a lot about 5 speeds and automatics with overdrive. That and the fact that if you go to the money and effort of putting in an engine, it is often cheaper and easier to put in the transmission made to go behind the new engine. Good luck with your swap.