Engine swap in '68

I've got a '68 Coupe and it currently has a 302 2v in it. The car is not original, I've had to have a lot of bodywork done and it's not the original engine in it, so what I'm thinking of doing is putting a big block in it. I know to do that I will need to change the whole drive train in it and the suspension, but my question is will a big block fit? I would like to put a 460 in it if possible, just not sure there's enough room. My goal is to run low 12's or better in it, but still be able to be a daily driver. It also has an automatic transmission in it, if I'm going to change the whole drive train, would it be too much trouble to put a manual tranny in it?

Thanks a lot, I'll definately look into that. I thought about getting a crate 302, but there's just something about a big block ya know. I'll probably end up getting a crate 460 too though if I can afford it.