Potential project Barracuda

I think I'm leaning towards tackling it pending further climbing around under the car, double checking the front end, and getting a second set of eyes on it in person for a sanity check. I'll poke around for the information myself, too, but any suggestions appreciated for a 300ish+ horsepower drivetrain that will fit easily (no firewall/engine bay cutting, stock engine mount locations a plus). Manual transmission would be preferred but open to decent autos. There is a clutch pedal assembly in the car for its current three-on-the-tree but I'm not sure if that really puts me ahead at all versus the auto probably being easier. It'd be a hole in the floor either way. If there's a common limited slip rearend that fits this car well that would also be good to know.

A 360 will flat accomplish the job but a pretty warm 318 will as well.....and if done right can even have some semblance of gas mileage. The 4" bore of the 360 is great for making power for sure, but the drawback is that it will burn a lot more fuel......that is if mileage is something that concerns you. A pretty warm 318, an 833 four speed over drive and some 3.55 gears would be a really nice combo in that light car. Hell, I have a stock 170 3 on the tree with 3.55s and I love it. It's peppy as can be.