Jon,
If you are talking LA 318 to 360 the answer is no, oil pan is different, flex plate is weighted on 360 but not 318 and the 360 motor mounts are different. If you are talking Magnum 318 to 360, the pans are the same, the flex plate can be either weighted on not on 360, not on 318 and the motor mounts are the same.
If you are looking to upgrade, the Magnum is a great choice as it has hypereutectic pistons, moly rings and better gasket than the LA 360 plus it was made in the last decade so finding a used one in usable shape is much more likely. The Magnums require an oil pan change for a car, then either LA front cover and V belts or Magnum cover and serpentine belts. The latter choice gives you better alternator(130A internally regulated vs 60A external), updated AC compressor if you have AC, saginaw PS pump and of course serp belt. If you prefer the old school classic look, swap your v bet stuff on it and bathe in nostalgia without all the oil leaks.
The Magnum heads flow much better than LA and provide a higher compression ratio for cam upgrades. You also get a hydraulic roller cam and lifters plus 1.6 ratio rockers on studs instead of shafts like LA. You can either run factory injection or a carb but will need an electric fuel pump if using Magnum timing cover due to no fuel pump hole. There are many threads about this, plus the magnumswap.com web site and we have lots of info on our site.
Feel free to call the shop at 541-955-0363 or pm if you have any questions about either swap.
Evan
