65 barracuda
The 360 will drop right in place of the 273 and the 904 bolts right up - as long as you don't have the push button shifter, which I don't think you do. The driver's side mount will need a couple of washers to take up the space difference between the block ears and the mount (about 1/4 inch on mine I believe), and you can weld a piece onto the mount to pick up the third mounting point on the block. As mentioned, you'll need either a B&M flexplate, or just a torque converter with the 360 balance weights on it. The only other thing to watch is the 7.25" rear end you probably have in there. Some of them aren't too strong, although I've been running one behind my modified 360 for about 18 years now and it's still going strong. The one before that lasted about 11 years behind a pretty strong 318. Good luck.