[BlackSS2005]

My friend bought a 77 Trans Am with 50000 original miles on it. It's been sitting for a while and he's doing a frame off restoration. We have looked at the build sheet from under the back seat and decifered somethings about it. The label on the shaker hood says 6.6 litre. I've read a few things on here saying it might be a 403, but I also read that there was no 403 in 1977. The build sheet says it's a 400 but just wanna make sure. He's also looking for advise on building the engine after we figure this out. He wants to buy a engine kit for the rebuild but not a stock one. He wants a mild cam and we aren't sure so I guess thats why we are on here asking.