diiulio,
Don't give up on the 460. Build the car the way you want to! The Weavers at Unique do install 460's in thier cars. Didn't use to but the demand was great enough that they had to. It is a tight fit but will work. In fact, they were working on one when I picked up mine in January.
All of the advice is good but the bottom line is that you are the one building the car and the one that has to be satisfied with the end results!
I should know. I put a cleveland in mine and painted it orange with white stripes
And you know what? Everyone loves the car
Have Fun!