What do i need to change to put a f350 super duty engine in a f250 super duty pickup

What is your question?

Do i need to change my transmission when i change my motor. I changed my 250 to a 350 motor but ny truck is now slow. It like it takes a long time to get going and i cant go faster than 40ish miles. So i cant drive on the freeway. What do i have to do in order to make my truck run good

How long has your 2006 Ford F-150 had this problem?

A week or 2