Moabdude,
I just read your car build post (I really just looked at pictures because I don't speak dutch) and watched the videos. Your 400sbc is awesome! You have a killer car. I would recommend a nicer/newer motor than a LS1. With that nice of a car Id recommend a crate LS3 since it will come to you in perfectly clean condition. Your car will be worth more also. Its really hard to get a used LS1 to look pretty since a lot of them are weathered. Your car is way too clean to put in a weathered motor.
Keep checking
www.ls1tech.com in the for sale section. There are new crate engines on there all the time for cheap.