Has anybody done this before?

You'll get flack, but who cares? I agree that there's nothing wrong with it as long as you're not lying about it when you try to sell it.

I put a 340 in a 67 Dart, but made it look like a hi-po 273. I'm not trying to fool anyone. I just like how it looks.

Or you could be just the opposite like me. My 70 swinger has a 408 crate and still wears the 340 badges on the scoops and has a 340 pie plate. Just never got around to changing anything. I would love to have 408 badges and pie tin but I havn't seen anything like that, sure would be cool though.