This 1971 Ford Boss 351 Mustang is a one year only car. It replaced the Boss 302 in the Mustang line-up. It was on the new body style for 71, and did not go over very well. Some say it is one of the most well rounded muscle cars ever.
This one was special ordered by the owner back in 71. He was color blind and thought it was red! When it was delivered his wife informed him it was yellow.
Around 1976 he started putting a 2-bbl on the car, and gave up half way through. It has been on the trailer from then until about 2021 when it was sold to the new owner. It was as legit a barn find as it gets. Tractors, hay, livestock. The works!
Source and more info : Auto Archaeology via Youtube