To the Island of Misfit Toys.
In the early 1970s my motorhead brother was given lots of odds and ends, including a Chevy Vega with a melted engine (they did that if they lost coolant) and a 454 with manual transmission attached. What to do? He measured it up, chopped out part of the firewall, and shoehorned the engine under the hood. (It was a lot easier in those days, when you could see the ground around both sides of the engine.) He said it went like lightning on freeway on-ramps but he had to slow way down to get around corners. It steered like... well, it didn't really steer as much as it was wished around corners. He kept it a month and parted it out again.
It would be a lot harder for you. There are only connections for four injectors and four spark plugs under the hood, and the ECU has no idea how to handle 8 cylinders, so the engine harness and ECU would have to be replaced with ones that probably don't exist. The existing front wheel drive is a problem; it will waste most of the torque of a V8 in useless wheel spin, and the chassis is not meant to have a driveshaft to the rear axle or to have the torque of the engine applied to it; the chassis would twist and stay twisted if you found a way to do it.
Now you have an idea why nobody has done it before.