You can dress that 270 to look like the original motor, but it will have much more power. They are great motors and I love the one I have. Swapping to a 270 will mostly just require putting mounts and linkages back to stock.
Installing a V-8 means crossmembers and exhaust complications and who knows what all else. I did a '41 but it was more than 30 years ago so I'll let others say what it will take.
As for transmission choices, if you are thinking Chevy V-8, or any GM V-8 for that matter, your transmissions options are basically the same for either motor. Any manual transmission that will work with a V-8 can be used on your 270 and modern type automatic transmissions can be adapted to the 270 also.
