I thought the Boss 351 was a 1971 only thing.....
There is a way to get a build sheet on your car from Ford. It is called the Marti Report. There is also a lady that has the ACTUAL invoice to every Mustang built. Her Name is Lois Eminger. I got one from her on a 69 Mach 1 that I had. It cost like $45.00. She actually sends the one and only original copy she has!
Man don't you wish that GM did that?