Here are some pics that I have come across of Boss Mustangs, which were produced from 1969-1971, and included the Boss 302 (1969-1970), Boss 351 (1971), and the Boss 429 (1969-1970).
Through 1969 and 1971, the Boss 302 and Boss 351 were at the forefront of Trans-Am road racing. The Boss 429 was crated by Ford to homologate the Boss 429 H/O engine for NASCAR racing purposes.
Click the links below to see the Boss 302, 351, and 429 pages.