I actually admire this guy's creativity, or simple lack of knowledge of the LSx. To me, this would be a no-brainer in favor of the LSx and T56. However, there are some interesting ideas in here.
I'm also curious about your neighbor's fascination with the 351M. This has been a problematic/anemic power plant for many people over the years. I'm sure they can be done properly with enough money, but then anything can in that respect.