Ok I have a 1980 Cutlass Supreme that previously had a 307 in there. The 307 and transmission are both gone and I’m replacing them with a 455 Oldsmobile out of a Ninety-Eight with 21K miles on it and comes with a the TH400 Trans bolted up with and the drive shaft. I’ve been told that this isn’t a simple drag and drop due to the driveshaft or transmission needing to be modified to fit the car. What should I do ? Get a TH350? Will it take this 455 with aftermarket Headers, Intake Manifold and has been done up to push out some major HP/Torque...