No better car to learn to work on than a slant 6 A body. Swap the seized 225 for the 225 you bought for $50, and get it running. It will be a great feeling of accomplishment, and you will get a chance to see whats involved in replacing the motor. Then you can tell that story for the rest of your life.
If you are dead set on a V8 swap, I’d still advise against the 65 wagon unless you can get it for $500 or less. It’s got $$$ in back fees and then you need to pull everything and recondition. Unless you want to swap in a clapped out grease pit.
How’s the rest of the car? Brakes and suspension good?